SCHEMA-295. Ability to override reader schemas in Kiji tables

- introduces CellDecoderProvider.
- refactor TestHBaseKijiRowData to get rid of deprecated constructor.
- HBaseKijiRowData has almost only one constructor.
- CellSpec now has a CellDecoderFactory.
- Test Avro records (Node/Edge) have proper default values.
- CellSpec supports "no reader schema" (ie. use writer schema).

issue: https://jira.kiji.org/browse/SCHEMA-295
review: https://review.kiji.org/r/289
SCHEMA-323. KijiReaderFactory to create custom readers.

- adds KijiTable.getReaderFactory().

issue: https://jira.kiji.org/browse/SCHEMA-323
review: https://review.kiji.org/r/284
SCHEMA-322. Restrict KijiRowData.getPager(family) to list the qualifiers in the family

- adds StripValueColumnFilter (cloned from StripValueRowFilter).
- update KijiPager documentation for map-type families.
- implement pager for map-type families, to retrieve qualifiers only.
- remove obsolete tests.

issue: https://jira.kiji.org/browse/SCHEMA-322
review: https://review.kiji.org/r/283
SCHEMA-339. Run unit-test against real HBase

issue: https://jira.kiji.org/browse/SCHEMA-339
review: https://review.kiji.org/r/315
SCHEMA-344. Fix pager unit-tests when run against real HBase

- Tests do not rely on page sizes anymore.
- KijiClientTest no longer sets deprecated configuration fs.default.name

issue: https://jira.kiji.org/browse/SCHEMA-344
review: https://review.kiji.org/r/347
SCHEMA-348. TestHBaseKijiTableReader doesn't use KijiClientTest

- also fixes a few other tests.

issue: https://jira.kiji.org/browse/SCHEMA-348
review: https://review.kiji.org/r/358
initial work on hbase 94 support.
Get pagination tests working on 0.94.

KijiPaginationFilter moved to impl package, contract revised.
Usage of KijiPaginationFilter restricted to internal cases.
Removed bogus application of KPFilter in HBaseDataRequestAdapter.

Other test cases revised to conform to requirements for KijiClientTest
portability.