[HBASE-10910] Make sure we do most optimal multiGets Revert

Author: adela

Summary:
This reverts commit d5d09c2b28b4f0bc3c33ebe8d7a92081f90fe89c.
Reverting because it breaks some unit tests and also breaks some expected behavior of get(List<Get>)

Test Plan: no need to test :)

Reviewers: daviddeng, fan, gauravm, manukranthk

Reviewed By: daviddeng

CC: hbase-eng@

Differential Revision: https://phabricator.fb.com/D1265457

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.89-fb@1586064 13f79535-47bb-0310-9956-ffa450edef68
[HBASE-2000] Move endpoints into separate package for better organization

Author: adela

Test Plan: N/A

Reviewers: daviddeng

Reviewed By: daviddeng

CC: hbase-eng@

Differential Revision: https://phabricator.fb.com/D1265777

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.89-fb@1586065 13f79535-47bb-0310-9956-ffa450edef68
[master] Make region readonly after the first flush completes during region close

Author: fan

Summary:
We need to use atomic booleans to disable mutations before the second flush starts. Otherwise IPC handler threads which are trying to mutate the region could be blocked on splitsAndClosesLock until the region is closed.
This diff gives IPC handler threads greater chance to return NSRE to clients immediately.

Test Plan: TestHRegionClose

Reviewers: liyintang, aaiyer

Reviewed By: liyintang

CC: hbase-dev@

Differential Revision: https://phabricator.fb.com/D1265645

Task ID: 4099120

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.89-fb@1586066 13f79535-47bb-0310-9956-ffa450edef68
[HBASE-6308] Add util coprocessor stuff - CoprocessorClassLoader

Author: adela

Summary: adding a custom class loader for coprocessors

Test Plan: will test later

Reviewers: daviddeng, elliott

Reviewed By: daviddeng

CC: hbase-eng@, arice, elliott, andrewcox

Differential Revision: https://phabricator.fb.com/D1262214

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.89-fb@1586067 13f79535-47bb-0310-9956-ffa450edef68