Convert genomic positions to any transcript

Add optional gene argument to the numberConvertion webservice method. If
present, it will convert genomic variants to any transcript of the given
gene, no matter how far away they are located (but on the same chromosome
of course). Fixes #70.



git-svn-id: https://humgenprojects.lumc.nl/svn/mutalyzer/trunk@402 eb6bd6ab-9ccd-42b9-aceb-e2899b4a52f1