[RocksJava] Memtables update to 3.6

- Adjusted HashLinkedList to 3.6.0
- Adjusted SkipList to 3.6.0
- Introduced a memtable test
Fix incorrectly merged Java - Makefile
Fixed cross platform build after introducing Java-7 dependencies
Fix timing
Merge pull request #354 from fyrz/RocksJava-memtables-3.6

[RocksJava] Memtables update to 3.6
Merge pull request #357 from fyrz/JavaTest-Fix

Fix issues introduced by latest Java additions