fix regression introduced by changeset: 1431:28e9d479aa65 [Use '-p' command line option when running matiec (iec2c)]

Variable matiec_flags in c_ext.py and PythonFileCTNMixin.py is not
used for flags for matiec (IEC to C compiler) actually, but it's used
to compile C-code generated for extensions using normal C-compiler,
like gcc.

fix display of ARRAY fields inside of structure data types.

Previously ARRAY fields in structures were displayed, for example,
like 'ARRAY [1..2] OF ARRAY' instead of 'ARRAY [1..2] OF INT'. Because
of this error the array type can be really edited.