HBASE-12569 Update scripts to control MaxDirectMemorySize via env vars

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

Conflicts:
	src/main/docbkx/book.xml
    HBASE-12404 Task 5 from parent: Replace internal HTable constructor use with
    HConnection#getTable (0.98, 0.99)

    Backport

    Replaced HTable under hbase-*/src/main/java. Skipped tests. Would take
    till end of time to do all and some cases are cryptic. Also skipped
    some mapreduce where HTable comes through in API. Can do both of
    these stragglers in another issue.
    Generally, if a utility class or standalone class, tried to pass in a
    Connection rather than have the utility or standalone create its own
    connection on each invocation; e.g. the Quota stuff. Where not possible,
    noted where invocation comes from... if test or hbck, didn't worry about
    it.
    Some classes are just standalone and nothing to be done to avoid
    a Connection setup per invocation (this is probably how it worked
    in the new HTable...days anyways). Some classes are not used:
    AggregationClient, FavoredNodes... we should just purge this stuff.
    Doc on what short circuit connection does (I can just use it...
    I thought it was just for short circuit but no, it switches dependent
    on where you are connecting).
    Changed HConnection to super Interface ClusterConnection where safe (
    internal usage by private classes only).
    Doc cleanup in example usage so we do new mode rather than the old
    fashion.
    Used java7 idiom that allows you avoid writing out finally to call close
    on implementations of Closeable.
    Added a RegistryFactory.. moved it out from being inner class.
    Added a utility createGetClosestRowOrBeforeReverseScan method to Scan
    to create a Scan that can ...
    Renamed getShortCircuitConnection as getConnection – users don't need
    to know what implementation does (that it can short-circuit RPC).
    The old name gave pause. I was frightened to use it thinking it only
    for short-circuit reading – that it would not do remote too.
    Squashed commit of the following:
HBASE-12128 Cache configuration and RpcController selection for Table in Connection
HBASE-12581 TestCellACLWithMultipleVersions failing since task 5 HBASE-12404 (HBASE-12404 addendum)