Review Board 1.7.22

HBASE-5620 Convert the client protocol of HRegionInterface to PB

Review Request #4629 - Created April 3, 2012 and submitted

Jimmy Xiang
This is the client protocol part of region interface. The admin protocol part will be done in a different jira.

The HRegionInterface is still there since the admin part is not done yet.  The other reason is that in case some people still wants the old interface

Filters, comparators and coprocessor parameters are still Writable.  They will be addressed in different jiras.

The existing client interface is not changed so that we don't break existing clients.
"mvn -PrunAllTests clean test" is green, except some flaky tests which need to run again.

Also tested it on a real cluster with ycsb and bigtop.
Review request changed
Updated (April 12, 2012, 10:33 p.m.)
Minor code change.  Fixed a bug.