contain two columns, Sample (String) and Fraction (Double) that form the Sample-Fraction map for the per-sample AlleleBiasedDownsampling.
-Integration tests to UnifiedGenotyper (Using artificially contaminated BAMs created from a mixure of two broadly concented samples) were added
-includes throwing an exception in HC if called using per-sample contamination file (not implemented); tested in a new integration test.
-(Note: HaplotypeCaller already has "Flat" contamination--using the same fraction for all samples--what it doesn't have is
_per-sample_ AlleleBiasedDownsampling, which is what has been added here to the UnifiedGenotyper.
-New class: DefaultHashMap (a Defaulting HashMap...) and new function: loadContaminationFile (which reads a Sample-Fraction file and returns a map).
-Unit tests to the new class and function are provided.
-Added tests to see that malformed contamination files are found and that spaces and tabs are now read properly.
-Merged the integration tests that pertain to biased downsampling, whether HaplotypeCaller or unifiedGenotyper, into a new IntegrationTest class.