More findbugs fixes
Change to use reference conn instead of client.connection
Merge pull request #485 from samarthjain/master

More findbugs fixes.
Have delete go through optimize, fix basic delete scenarios for mutable secondary indexing, cast and invert column if necessary when index being used instead of table
Fix bug introduced by find bug changes
Short-circuit building index state when we know we're doing a row deletion, serialize data table empty key value column family so we can detect row deletion reliably, look for index metadata for operations run on the server side, adding license header to files where it was found to be missing
Bug fixes for put/delete generation for mutable indexes, fixes for coercing index column refs, parameterize QueryExecTest and rename to QueryTest
Reducing max memory, fixing javadoc warning
Going back to translating query to index query once
Going back to default QueryTest
Reduce some mutable index logging to trace to get 20x unit test speedup, parameterized QueryTest to run tests against table with various mutable index configurations, correctly apply coerce to RHS when index table used, fix visit walking for Expression with no explicit visit method, maintain IN list key child expressions on client side
Work around mutable secondary index bug where old deleted state is being used by destroying hbase tables between parameterized runs
Removed comment
Add null check in NotExpression
Fixing filtering deletes for indexing.

The logic there was just flat wrong. It was pretty close to right, but had some minor cases taht
lead to wrong answers in some cases
Bug fix for handling index maintanence for null->not null value for composite index key (will add test in follow up commit)