bulk of lexer/parser, based on Parametric Fortran by Martin Erwig
updated for cabal build
some small simplifications
ifstmt removed from pretty printer (missed this somehow before)
fix to allow programs with no internal subprograms
fixed definition of 'main' programs to allow 'contains' block- a few other tweaks@
Merge pull request #1 from dorchard/master

merged Martin Erwig's base code from Parametric Fortran