Revert back to gmap 2014 12 23

During the clinical validation, it became clear that several variants that are found with the 2014-12-23 version of GMAP are no longer found with the latest version (currently 2020-06-04). These issues have been reported and will be fixed in a future version of gmap.

These variants were also added to the HAMLET test suite, and gmap was reverted back to the old version from 2014-12-23, since this version detects all variants.