Java port update

Added Java (Android) test case which check whether the Java HUSL port complies with the 2.×.× snapshot.
Updated the Java port, so it complies with the snapshot in part. Specifically: the Java port now works according to the snapshot when converting RGB ↔ XYZ ↔ LUV ↔ LCH ↔ HUSL; but not when converting RGB ↔ XYZ ↔ LUV ↔ LCH ↔ HUSLp. (HUSLp conversion is missing.)

Note that only RGB → XYZ → LUV → LCH → HUSL v HUSLp is tested by the test case. RGB ← XYZ ← LUV ← LCH ← HUSL v HUSLp isn't.