[Java] 1. Moved BitUtil to the u.c.r.sbe.codec.java package (it is relat...

...ed more to the java codec than the util package)
BitUtil is tied at this point to DirectBuffer Implementation and this is why I believe it should stay in the same package with DirectBuffer class. 

2. Moved JavaUtil to u.c.r.sbe.generation.java (apparently each generator has its own Util class)
3. Code tidy for protobuf based MarketDataBenchmark.