Updating .gitignore

Adding temp files (ending in ~), as well as key files in the vcfstreamer
directory (such as .o, .a files, etc.)
Adding a Google Test-based unit testing skeleton.

GTest is the Google C++ Unit Testing framework,
https://code.google.com/p/googletest/

This commit includes a skeleton .cpp file for writing tests, as well as
the Makefile updates to compile an executable to run the tests
(vcfstreamer_test).

Compiling now requires having the GTEST repository
cloned somewhere on the current machine, in order to build libgtest.a --
on salty, this is installed in /home/bio/tdanford/googletest but we
should make this a build parameter in the future.
[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.