Merge pull request #45 from harveyfeng/shark-0.11

Some changes to build files for pushing to Sonatype/Maven Central
Fixed concurrency problem in HiveHistory.java (contributed originally by @kayousterhout)
Fix bug of boolean equals() method, the reference comparison works incorrectly after deserialization.

Originally contributed by @chenghao-intel
Fix NullPointerException for Constant Null value

Originally contributed by @chenghao-intel
Reduce lock contention in ExprNodeGenericFuncEvaluator and ShimLoader.

Originally contributed by @chenghao-intel.
Merge pull request #46 from rxin/fixes

Apply some important fixes again for Hive 0.11
Changed Hive version to 0.11.0-shark-0.9.1.
Some mods to build files for publishing javadoc and sources jars.
Merge tag '0.11.0-shark-0.9.1' into shark-0.11

Hive 0.11 for Shark 0.9.1 release