Updating .gitignore

Adding temp files (ending in ~), as well as key files in the vcfstreamer
directory (such as .o, .a files, etc.)
Skeleton code for writing tests using GTest.
[VCF-1] Updating schema/parser to be flexible

Updating the variant schema and parser to be more flexible -- the
high-level changes here involve removing the MULT_VAL array, and storing
a lot of the other fields in a generic blob/string field which can be
parsed out later.

The initial change here removes the KGENOMES_MULT_VAL array from the
kgenomes schema file.