HBASE-12139 StochasticLoadBalancer doesn't work on large lightly loaded clusters

Summary:
Currently the move cost overshadows the skew cost on a large cluster. This can render the split policy worse than useless
and it can trap meta on the most loaded server in the cluster.

Test Plan:
Unit tests everywhere
likeaboss

Reviewers: stack, manukranthk

Subscribers: tedyu

Differential Revision: https://reviews.facebook.net/D24285
HBASE-12143 Minor fix for Table code (Solomon Duskis)
HBASE-11804 Raise default heap size if unspecified
HBASE-12130 HBASE-11980 calls hflush and hsync doing near double the syncing work
HBASE-11930 Document new permission check to roll WAL writer (Jerry He)
HBASE-12065 Import tool is not restoring multiple DeleteFamily markers of a row (Maddineni Sukumar)
Try adding javadoc url to email output
HBASE-12145 Fix javadoc and findbugs so new folks aren't freaked when they see them

Fix javadoc warnings.

Fixup findbugs warnings mostly by adding annotations saying 'working as expected'.

In RpcRetryingCallerWithReadReplicas made following change which findbugs spotted:

-        if (completed == null) tasks.wait();
+        while (completed == null) tasks.wait();

In RecoverableZooKeeper, made all zk accesses synchronized -- we were doing it
half-ways previously.

In RatioBasedCompactionPolicy we were making an instance of Random on
each invocation of getNextMajorCompactionTime
HBASE-12078 Missing Data when scanning using PREFIX_TREE DATA-BLOCK-ENCODING

Signed-off-by: Andrew Purtell <apurtell@apache.org>
HBASE-12120 HBase shell doesn't allow deleting of a cell by user with W-only permissions to it (Srikanth Srungarapu)
HBASE-12127 Move the core Connection creation functionality into ConnectionFactory (Solomon Duskis)
HBASE-12140 Add ConnectionFactory.createConnection() to create using default HBaseConfiguration. (Jean-Marc Spaggiari))
HBASE-12153 Fixing TestReplicaWithCluster (Manukranth Kolloju)
HBASE-12156 TableName cache doesn't used for once of valueOf methods (Andrey Stepachev)
HBASE-12152 TestLoadIncrementalHFiles shows up as zombie test; ADD TIMEOUT ON TESTS
HBASE-12133 Add FastLongHistogram for metric computation (Yi Deng)
HBASE-12158 TestHttpServerLifecycle.testStartedServerWithRequestLog goes zombie on occasion
HBASE-12149 TestRegionPlacement is failing undeterministically (Manukranth Kolloju)
HBASE-12133 Add FastLongHistogram for metric computation; ADDENDUM TO FIX BROKE COMPILE
HBASE-12148 Remove TimeRangeTracker as point of contention when many threads writing a Store