ACCUMULO-2170 Update CHANGES for 1.5.1 from jira.
Merge branch '1.5.1-SNAPSHOT' into 1.6.0-SNAPSHOT

Conflicts:
	CHANGES
Merge branch '1.6.0-SNAPSHOT'
ACCUMULO-1930 Adding StatsCombiner and Classpath test
ACCUMULO-2317 fixing shell
Merge remote-tracking branch 'origin/1.6.0-SNAPSHOT'