descriptions, added a presentation about Mutalyzer.

Mutalyzer.py:
- Added a fix for a bug that was triggered when an expected frameshift leads to
  no change.

Parser.py:
- Added iupac codes as allowed nucleotides.



git-svn-id: https://humgenprojects.lumc.nl/svn/mutalyzer/trunk@192 eb6bd6ab-9ccd-42b9-aceb-e2899b4a52f1