 is extended: dimensions are moved to variable definitions
Note: f2py directive: <commentchar>f2py<line> is read as <line>
Note: pythonmodule is introduced to represent Python module

Usage:
  `postlist=crackfortran(files)`
  `postlist` contains declaration information read from the list of files `files`.
  `crack2fortran(postlist)` returns a fortran code to be saved to pyf-file

  `postlist` has the following structure:
 *** it is a list of dictionaries containing `blocks':
     B = {'block','body','vars','parent_block'[,'name','prefix','args','result',
          'implicit','externals','interfaced','common','sortvars',
          'commonvars','note']}
     B['block'] = 'interface' | 'function' | 'subroutine' | 'module' |
                  'program' | 'block data' | 'type' | 'pythonmodule' |
                  'abstract interface'
     B['body'] --- list containing `subblocks' with the same structure as `blocks'
     B['parent_block'] --- dictionary of a parent block:
                             C['body'][<index>]['parent_block'] is C
     B['vars'] --- dictionary of variable definitions
     B['sortvars'] --- dictionary of variable definitions sorted by dependence (independent first)
     B['name'] --- name of the block (not if B['block']=='interface')
     B['prefix'] --- prefix string (only if B['block']=='function')
     B['args'] --- list of argument names if B['block']== 'function' | 'subroutine'
     B['result'] --- name of the return value (only if B['block']=='function')
     B['implicit'] --- dictionary {'a':<variable definition>,'b':...} | None
     B['externals'] --- list of variables being external
     B['interfaced'] --- list of variables being external and defined
     B['common'] --- dictionary of common blocks (list of objects)
     B['commonvars'] --- list of variables used in common blocks (dimensions are moved to variable definitions)
     B['from'] --- string showing the 'parents' of the current block
     B['use'] --- dictionary of modules used in current block:
         {<modulename>:{['only':<0|1>],['map':{<local_name1>:<use_name1>,...}]}}
     B['note'] --- list of LaTeX comments on the block
     B['f2pyenhancements'] --- optional dictionary
          {'threadsafe':'','fortranname':<name>,
           'callstatement':<C-expr>|<multi-line block>,
           'callprotoargument':<C-expr-list>,
           'usercode':<multi-line block>|<list of multi-line blocks>,
           'pymethoddef:<multi-line block>'
           }
     B['entry'] --- dictionary {entryname:argslist,..}
     B['varnames'] --- list of variable names given in the order of reading the
                       Fortran code, useful for derived types.
     B['saved_interface'] --- a string of scanned routine signature, defines explicit interface
 *** Variable definition is a dictionary
     D = B['vars'][<variable name>] =
     {'typespec'[,'attrspec','kindselector','charselector','=','typename']}
     D['typespec'] = 'byte' | 'character' | 'complex' | 'double complex' |
                     'double precision' | 'integer' | 'logical' | 'real' | 'type'
     D['attrspec'] --- list of attributes (e.g. 'dimension(<arrayspec>)',
                       'external','intent(in|out|inout|hide|c|callback|cache|aligned4|aligned8|aligned16)',
                       'optional','required', etc)
     K = D['kindselector'] = {['*','kind']} (only if D['typespec'] =
                         'complex' | 'integer' | 'logical' | 'real' )
     C = D['charselector'] = {['*','len','kind','f2py_len']}
                             (only if D['typespec']=='character')
     D['='] --- initialization expression string
     D['typename'] --- name of the type if D['typespec']=='type'
     D['dimension'] --- list of dimension bounds
     D['intent'] --- list of intent specifications
     D['depend'] --- list of variable names on which current variable depends on
     D['check'] --- list of C-expressions; if C-expr returns zero, exception is raised
     D['note'] --- list of LaTeX comments on the variable
 *** Meaning of kind/char selectors (few examples):
     D['typespec>']*K['*']
     D['typespec'](kind=K['kind'])
     character*C['*']
     character(len=C['len'],kind=C['kind'], f2py_len=C['f2py_len'])
     (see also fortran type declaration statement formats below)

Fortran 90 type declaration statement format (F77 is subset of F90)
====================================================================
(Main source: IBM XL Fortran 5.1 Language Reference Manual)
type declaration = <typespec> [[<attrspec>]::] <entitydecl>
<typespec> = byte                          |
             character[<charselector>]     |
             complex[<kindselector>]       |
             double complex                |
             double precision              |
             integer[<kindselector>]       |
             logical[<kindselector>]       |
             real[<kindselector>]          |
             type(<typename>)
<charselector> = * <charlen>               |
             ([len=]<len>[,[kind=]<kind>]) |
             (kind=<kind>[,len=<len>])
<kindselector> = * <intlen>                |
             ([kind=]<kind>)
<attrspec> = comma separated list of attributes.
             Only the following attributes are used in
             building up the interface:
                external
                (parameter --- affects '=' key)
                optional
                intent
             Other attributes are ignored.
<intentspec> = in | out | inout
<arrayspec> = comma separated list of dimension bounds.
<entitydecl> = <name> [[*<charlen>][(<arrayspec>)] | [(<arrayspec>)]*<charlen>]
                      [/<init_expr>/ | =<init_expr>] [,<entitydecl>]

In addition, the following attributes are used: check,depend,note

TODO:
    * Apply 'parameter' attribute (e.g. 'integer parameter :: i=2' 'real x(i)'
                                   -> 'real x(2)')
    The above may be solved by creating appropriate preprocessor program, for example.

