DRILL-1470 : cast into varchar should recognize the length parameter in varchar. Fix casting function implementation: the length parameter should mean # of chars, not # of bytes.

New unit test case to verify the result from cast function.

Fix bug in cast into varchar. When target length = 0, it means we want to keep the input .

code clean up.

Include change for varbinary cast as well.
DRILL-1592: Detect drillbit failure and cancel the affected running queries.

Revise code based on review comments.

Revise code based on comments: only track the newly dead drillbits.

Remove some debug msg.

Minor code change based on review comments.

clean up.

add comment. Clear listeners when drillbit is unregistered from CC.

Minor code change from review comments.
DRILL-1638: display list of files in the logical plan
DRILL-1660: adding a test case to cover an array of empty and null valued objects.
i) remove redundant guard statement from JsonRecordReader2
ii) rename unit test suite
DRILL-1684, DRILL-1517: Profile and cancellation updates
- Remove any storage of persisted profiles.
- Store a separate query info object for active queries.
- Update cancellation and running profile loading to query foreman server.
- Make file store support HDFS APIs
- Update PStoreProvider to use configuration to decide if you want PERSISTENT, EPHEMERAL, or BLOB storage rather than separate interfaces.
- Update ZkPStore's persistent mode to leverage a cache and respond to changes rather than actively probing values.
- Update ZkPStore's cache to be effectively write-through.
- Automatically delete deprecated or default value options from PStore.
DRILL-1591, DRILL-1676: Move javascript resources to local serving and update dagre-d3 to older version (2.9).  Update profile page.
DRILL-1656: Fix wildcard queries to correctly determine selection root.
DRILL-1639: Close Hive resources
DRILL-1678: Add fragment and operator id to label in plan visualizer
DRILL-1675: Add method to get QueryId from DrillResultSet
DRILL-1674: Set schema in WriterRecordBatch
DRILL-1659: Increase default maxWidth for sqlline to 10k
DRILL-1648: Fix for fast schema issue that was causing compilation issues in downstream operators.
DRILL-1647: Enable rewrite rule to allow multiple flattens in s a select clause. Fixes a few outstanding issues that were the reason for disabling it.

Fix for the failed Regression test run. Was an issue with removing cast information, simply needed to return the original expression rather than try to clone it if rewriting was not needed.

Was not visiting the child of a project appropriately, this was causing complex expressions nested inside of a sub-query to fail.
DRILL-1643, DRILL-1665: Flatten fixes
 - Fix repeated map vector to correctly report value count
 - Update flatten so init variables are reset for each new batch.
DRILL-1671, DRILL-1653, DRILL-1652: Fixes for flatten bugs
Add handling when a null exception is logged.
Remove extraneous System.out.print statements.