0.8-RC4

• use Float.compare and Double.compare in Comparators class to increase perf (insert/delete)
• use Float.compare instead of boxing primitives and calling compareTo. Should help performance of SplitterRStar (insert/delete)
• don't extract point from flatbuffers data structure more than required (improves performance) in FlatBuffersHelper.toGeometry
• fix infinite loop when rectangleGeographic called with double parameters (introduced in 0.8)
• switch order of compare parameters instead of negating result because of possbility of problems at Integer.MIN_VALUE being negated
• handle serialization of empty trees correctly