Update dependency versions for release.
[maven-release-plugin] prepare release kiji-express-0.5.0
[maven-release-plugin] prepare for next development iteration
EXP-78. Capture all errors when validating model
definitions and environments.

This commit captures and reports to the user all model
definition and environment validation errors.

Reviewed by: kiyan
EXP-93. Fixes bug in writing null values in the generic api.

Reviewed by: kiyan

issue: https://jira.kiji.org/EXP-93
EXP-96. Adds validation for KijiTaps before launching jobs.

review: https://review.kiji.org/r/728
issue: https://jira.kiji.org/EXP-96
EXP-100. Regression testing against latest KijiSchema/MR snapshots.
EXP-95. Provides more AvroRecord factory methods.

issue: https://jira.kiji.org/browse/EXP-95
review: https://review.kiji.org/r/747
EXP-94. Provides a temporary fix for writing empty AvroLists and AvroMaps.

issue: https://jira.kiji.org/browse/EXP-94
review: https://review.kiji.org/r/740
EXP-83. replaceMissingWith() expects a KijiSlice, but KijiSlice does not have a public constructor.

issue: https://jira.kiji.org/browse/EXP-83
review: https://review.kiji.org/r/735
EXP-89. Column qualifiers must start with a-zA-z_, but this
is not always the case with map-type column families.

This commit removes the incorrect validation of map-type column qualifiers
and adds a test to KijiSourceSuite, using mapSlice() to test map-type
column qualifiers with numeric-initial string names.

Reviewed by: kiyan
Update RELEASE_NOTES.txt for release.

Reviewed by: daisy