EXP-282. Cannot pack to specific objects with snake_case fields

review: https://review.kiji.org/r/1333
issue: https://jira.kiji.org/EXP-282
EXP-286. rename ColumnRequestInput#schema -> schemaSpec.

issue: https://jira.kiji.org/browse/EXP-286
review: https://review.kiji.org/r/1338
EXP-275. Make the missing column values option for KijiInput more extensible.

issue: https://jira.kiji.org/browse/EXP-275
review: https://review.kiji.org/r/1339
EXP-291. Fix AvroTupleConversions serialization bug

issue: https://jira.kiji.org/browse/EXP-291
review: https://review.kiji.org/r/1348
EXP-292. Modfiy testing framework to return avro records of the correct type (specific or generic).

issue: https://jira.kiji.org/browse/EXP-292
review: https://review.kiji.org/r/1350
Update dependencies for BentoBox 1.2.6 consistency.
Remove MR flags from `express jar` command.

These flags could interfere with arbitrary jars that use
positional arguments.
EXP-221. Improve the KijiSlice and PagedKijiSlice APIs.

issue: https://jira.kiji.org/browse/EXP-221

contributed-by: akahn (adam kahn, akahn@wibidata.com)
review: https://review.kiji.org/r/1341
EXP-301. Fix the issue of writing to HFiles belonging to layout 1.3 tables.

When writing to an HFile whose columns are validated in DEVELOPER or STRICT
mode, Schema throws an exception because the cell spec has no column URI. This
was fixed by using a different encoder wrapper that sets the URI of the cell
spec. Along the way, also fixed a problem in how source/sink fields are set
which prevents duplicate field exceptions in Cascading.

Reviewer: robert
EXP-298. Rename ColumnRequest[Input|Output] to Column[Input|Output]Spec

issue: https://jira.kiji.org/browse/EXP-298
review: https://review.kiji.org/r/1365
EXP-302. Remove references to KijiSlice from kiji-express.

issue: https://jira.kiji.org/browse/EXP-302
review: https://review.kiji.org/r/1368
EXP-259.  Finalize annotations for KijiExpress.

review: https://review.kiji.org/r/1356
issue: https://jira.kiji.org/EXP-259
EXP-155. Ensure all packages have documented package objects.

issue: https://jira.kiji.org/browse/EXP-155
review: https://review.kiji.org/r/1374
EXP-305. cleanup Express package structure

review: https://review.kiji.org/r/1379
issue: https://jira.kiji.org/EXP-305
EXP-158. Remove ScoreProducerJobTool.scala in org.kiji.express.tool

issue: https://jira.kiji.org/browse/EXP-158
review: https://review.kiji.org/r/1376
EXP-306. Fix access modifiers on various classes.

issue: https://jira.kiji.org/browse/EXP-306
review: https://review.kiji.org/r/1375
Updates express script for package move.

Over-the-shoulder reviewed by: robertchu
Update versions for Chirashi 1.2.6 release
[maven-release-plugin] prepare release kiji-express-0.12.0
[maven-release-plugin] prepare for next development iteration