Grammar:
   - Remove extra injections to make the AST looks nicer
   - Optimize sort exports to remove sdfchecker warnings
   - Add module extension
   - Separate modules for files
   - Add examples from:
     http://www.co.umist.ac.uk/SupportWeb/Unix/VDMTools/vdm-sl/examples
     (most examples use IFAD extensions)
   - Add "mk_" -/- [\ \n\t]
     
Haskell:
   - Improve the pretty-printer
   - Add tests for VDMhparser (e.g. trying to parse what was pretty-printed)