SCHEMA-647. Avro value parser does not support comments

issue: https://jira.kiji.org/browse/SCHEMA-647
review: https://review.kiji.org/r/1617
SCHEMA-649. Tiny bug in kiji-schema-extras Avro value parser

 - Fix typo in unit-test

issue: https://jira.kiji.org/browse/SCHEMA-649
review: https://review.kiji.org/r/1619
SCHEMA-650. KijiTableReaderPool should retain the table from which its readers read.

issue: https://jira.kiji.org/browse/SCHEMA-650
review: https://review.kiji.org/r/1626
SCHEMA-491. Share/reuse ZooKeeperClient instances when possible

issue: https://jira.kiji.org/browse/SCHEMA-491
review: https://review.kiji.org/r/1621
SCHEMA-651. cleanup deleted instances from zookeeper in /kiji-schema/instances

issue: https://jira.kiji.org/browse/SCHEMA-651
review: https://review.kiji.org/r/1634
SCHEMA-655. cleanup ZooKeeperClient resource leaks

issue: https://jira.kiji.org/browse/SCHEMA-655
review: https://review.kiji.org/r/1638
Bridge updates.
Adds experimental support for non-CDH5 HBase 96.
Fixes copyright year.
Updates to CDH5b2. Adds factory methods for ByteArrayComparable filters to bridge.