SCHEMA-418. ZooKeeperClient logs are too verbose

Lowers logging verbosity of ZooKeeperClient from info to debug.

issue: https://jira.kiji.org/browse/SCHEMA-418
review: https://review.kiji.org/r/643
SCHEMA-419. Bogus log statement in FormattedEntityId

Fixes log statement in FormattedEntityId.

review: https://review.kiji.org/r/633
issue: https://jira.kiji.org/browse/SCHEMA-419
contributed-by: jeffkole (Jeff Kolesky, jeff.kolesky@gmail.com)
SCHEMA-409. Add caching of AvroCellEncoders to table writers.

issue: https://jira.kiji.org/browse/SCHEMA-409
review: https://review.kiji.org/r/623
SCHEMA-416. HBaseKijiRowScanner imports Arrays from a scala package

Fixed to use java.util.Arrays.

issue: https://jira.kiji.org/browse/SCHEMA-416
review: https://review.kiji.org/r/648
SCHEMA-420. KijiTableLayout#validateCellSchema tolerates null schema values.

review: https://review.kiji.org/r/652
issue: https://jira.kiji.org/SCHEMA-420
reviewers: taton,robertchu
SCHEMA-407. Provide easy to use helper classes around pagers.

Adds iterators wrapping KijiRowData.getPager() to:
 - iterate through the versions in a column;
 - iterate through the qualifier names in a map-type family;
 - iterate through the versions in all columns in a map-type family.

issue: https://jira.kiji.org/browse/SCHEMA-407
review: https://review.kiji.org/r/615
SCHEMA-425. KijiTableLayout.getDesc() should return deep copy

review: https://review.kiji.org/r/662
issue: https://jira.kiji.org/SCHEMA-425