Draft update for compatibility w/current libsgp4.
Primarily consists of date and time handling name changes. Test results still need to be reviewed; they differ from previously expected results, but possibly within tolerances due to refinements in libsgp4. Will not currently build on OS X due to current libsgp4 usage of clock_gettime().
Updated test case references to reflect current libsgp4 output
Added minimal readmes for scrap test directories
Delete redundant test reference files. Aggregate reference files used for diff testing.
Bundling libs in gtg repository