Accept IVS locations in Variant_info LOVD interface

The fix is a hack, basically copying the same functionality from the
namechecker. I think this should eventually be merged somehow.

Fixes #63


git-svn-id: https://humgenprojects.lumc.nl/svn/mutalyzer/trunk@387 eb6bd6ab-9ccd-42b9-aceb-e2899b4a52f1