Refactored HBase region count configuration

Added a new option, regions-per-server, that takes effect if
region-count is unset.  When it takes effect, Titan's table is created
with total region count = (number of servers reported by HBase
ClusterStatus) * (regions-per-server).

If neither option is set, then the HBase manager still calls
HBaseAdmin#createTable(String) without specifying any rowkey
boundaries or region count.
Adding debug log msgs around storage failures
Naive HBase deprecation fix

This removes references to now-deprecated HBase API methods.  However,
it uses the simple approach to connection pooling recommended by the
HConnectionManager API @
http://hbase.apache.org/apidocs/org/apache/hadoop/hbase/client/HConnectionManager.html.

The problem with this is twofold:

* it's very slow -- even a tiny lock write takes on average 125 ms on
  my test machine, perhaps because of the heavyweight setup inside
  HConnection's implementation, which includes creating an executor

* my use of the HConnectionManager API may be leaking connections,
  because midway through the 0.94 test suite, the tests start dying
  with "Too many open files" when attempting to instantiate
  org.apache.zookeeper.ClientCnxnSocketNIO
Refactor HBase connection handling

Now HBase manager is 1-to-1 with HConnection.  Each manager creates
its single HConnection during construction and assigns it to a final
field.  However, every method is responsible for calling
connection.getTable(String) and closing the returned table object in a
finally block.  These HTableInterface instances on the stack are not
thread safe.  The HConnection is only closed when the manager is
closed.

Compared to creating an HConnection on the stack each method, this
approach is faster and does not cause too many open files errors
during testing.
Suppress HConnectionManager exception warning

The method HConnectionManager.createConnection throws a narrower class
of of Exceptions in 0.94 and a wider class (proper superset of types)
in 0.96.  Catch the wider set and silence a warning about exception
hiding that appears when compiling against 0.94.
Deleting commented code in HBaseStoreManager
Cleanup HBase method visibility and ordering

Moved private methods to end of class definitions, moved public
override methods to top, combined a pair of static initializer blocks,
made some public methods in HBaseKCVS private
Javadocs for ConfigOption enum

I just converted the existing regular comments next to each
ConfigOption enum value into javadoc comments preceding their
respective values
Removing titan-persisitit

master's copy of titan-persistit has migrated to the
titan-experimental repository

titan-site/src/site-resources/index.html
Add DEBUG logging of Cassandra consistency levels