modify TenantCacheImpl and HashCacheClient for equi-joins
code refine
Merge https://github.com/forcedotcom/phoenix

Conflicts:
	src/main/java/com/salesforce/phoenix/cache/TenantCacheImpl.java
	src/main/java/com/salesforce/phoenix/join/HashCacheClient.java
Merge pull request #309 from maryannxue/master

Issue 20 - part 1: hash cache modification