Fix+Enhancements
- did some optimization to get 2.x performance closer to 1.x
- added (optional) off heap configuration using unsafe to read/write values
- added simple api (see DefaultCoder) to directly serialize from/to byte arrays without the need for streams
- added possibility to directly serialize from/to offheap memory (long adr) zero copy (see OffHeapCoder, OnHeapCoder).
- added Long2Object Offheap hashmap
- fixed bug in offheap map