HBASE-12375 LoadIncrementalHFiles fails to load data in table when CF name starts with '_'

Signed-off-by: stack <stack@apache.org>
HBASE-12381 use the Maven Enforcer Plugin to check maven and java versions.

Signed-off-by: stack <stack@apache.org>

Conflicts:
	pom.xml
HBASE-12384 TestTags can hang on fast test hosts
HBASE-12274 addendum removes synchronized keyword for nextRaw()