HBASE-11331 [blockcache] lazy block decompression

When hbase.block.data.cachecompressed=true, DATA (and ENCODED_DATA) blocks are
cached in the BlockCache in their on-disk format. This is different from the
default behavior, which decompresses and decrypts a block before caching.
HBASE-11932 Docbook html-single build improvements
HBASE-11942 Fix TestHRegionBusyWait
HBASE-11934 Support KeyValueCodec to encode non KeyValue cells. (Anoop Sam John)
HBASE-11947 NoSuchElementException in balancer for master regions (Sergey Soldatov and Jimmy Xiang)
HBASE-11619 Remove unused test class from TestHLogSplit (Mikhail Antonov)
HBASE-11936 IsolationLevel must be attribute of a Query not a Scan (Vladimir Rodionov)
HBASE-11760 Tighten up region state transition
HBASE-11845 HFile tool should implement Tool, disable blockcache by default

HFileTool now accepts configuration via -D arguments. The blockcache is
disabled by default.
Added continuuity meetup to home page
HBASE-11946 Fix a change to the POM that broke building apidocs and xrefs
HBASE-11845 addendum
HBASE-11897 Add append and remove peer table-cfs cmds for replication (Liu Shaoqui)
HBASE-11935 ZooKeeper connection storm after queue failover with slave cluster down (Sukumar Maddineni)

Synchronize peer cluster connection attempts to avoid races and rate
limit connections when multiple replication sources try to connect to
the peer cluster. If the peer cluster is down we can get out of control
over time.