Revision 646104

HBASE-521   Improve client scanner interface

-Removed HScannerInterface and HInternalScannerInterface
-Created new interfaces Scanner for clients and InternalScanner for internal consumers
-Internal and client scanners no longer share common interface
-Client scanner's next() method and iterables are in RowResults
-Updated tests and internal consumers to use Scanner in place of HScannerInterface
-HTable obtainScanner(*) are now renamed getScanner(*)
-Tests have ScannerIncommon to turn Scanners into InternalScanners for some tests
-Fixed a bug in HMaster that was eating TableExistsExceptions (unrelated)
-Updated TableInputFormat to provide RowResults instead of MapWritables
-Updated TableOutputFormat to take BatchUpdates instead of MapWritables
-Updated TableMap, TableReduce, and friends to correctly hook up to new input/output formats

HBASE-567   Reused BatchUpdate instances accumulate BatchOperations
- Fix to BatchUpdate that allows correct reuse of BatchUpdate instances (readFields didn't clear BatchOperation map)
- Update TestSerialization to prove above is fixed