SCHEMA-695. Rebase and merge all Cassandra code onto master

issue: https://jira.kiji.org/browse/SCHEMA-695
review: https://review.kiji.org/r/1963
SCHEMA-842.  Translate eid components names to C* col names.

Avoid conflicts with CQL keywords, other columns (e.g., "version") in
the Cassandra Kiji tables.

review: https://review.kiji.org/r/1970
issue: https://jira.kiji.org/SCHEMA-842
SCHEMA-833. HBase Filters don't seem to work on 0.96.

issue: https://jira.kiji.org/browse/SCHEMA-833
review: https://review.kiji.org/r/1968
SCHEMA-847. Typo in KijiRowData: 'existant' should be 'existent'.

issue: https://jira.kiji.org/browse/SCHEMA-847
review: https://review.kiji.org/r/1975
over-the-shoulder-reviewers: ['ajprax']
SCHEMA-846. Add index on lg column in C* Schema.

Necessary because previously Cassandra KijiSchema died on row scans in
tables that have entity IDs with more than one component.

issue: https://jira.kiji.org/browse/SCHEMA-846
review: https://review.kiji.org/r/1976
SCHEMA-853. Cassandra KijiSchema should use version 2.0.3 of DataStax Java driver

issue: https://jira.kiji.org/browse/SCHEMA-853
review: https://review.kiji.org/r/1980
SCHEMA-850. Cassandra does not always create secondary indices properly when creating Kiji tables on a cluster

issue: https://jira.kiji.org/browse/SCHEMA-850
review: https://review.kiji.org/r/1981
SCHEMA-848. Fix DebugResourceTracker failing due to hash collisions

issue: https://jira.kiji.org/browse/SCHEMA-848
review: https://review.kiji.org/r/1977
SCHEMA-851. Deprecate CellSpec table reader overrides; fix hashCode & equality of KijiDataRequest; cleanups to CellDecoderProvider

issue: https://jira.kiji.org/browse/SCHEMA-851
review: https://review.kiji.org/r/1979
SCHEMA-840. Iterable based (instead of iterator based) KijiResult API

issue: https://jira.kiji.org/browse/SCHEMA-840
review: https://review.kiji.org/r/1965