EXP-160. Fix tutorial after refactoring extractors.

Review: https://review.kiji.org/r/977/
Reviewed by: robertchu
Update dependencies for release.
Updated RELEASE_NOTES.txt for release.
[maven-release-plugin] prepare release kiji-express-music-0.7.0
[maven-release-plugin] prepare for next development iteration
EXP-147 Wrapped lines longer than 92 characters so they don't wrap badly in gistit in the tutorial posts.
POM-9. Upgrade to Avro 1.7.5

issue: https://jira.kiji.org/browse/POM-9
review: https://review.kiji.org/r/1004
EXP-178. Get rid of all Avro unions in ModelDef and ModelEnv.

issue: https://jira.kiji.org/browse/EXP-178
review: https://review.kiji.org/r/1021
POM-22. Release root pom version 1.1.3

issue: https://jira.kiji.org/browse/POM-22
review: https://review.kiji.org/r/1086
EXP-206. Fix tutorial layout

issue: https://jira.kiji.org/browse/EXP-206
review: https://review.kiji.org/r/1153
Update versions for Chirashi 1.2.0 release.
Specify schemas when requesting columns.
[maven-release-plugin] prepare release kiji-express-music-0.8.0
[maven-release-plugin] prepare for next development iteration
Updates model definition and environment.

Reviewed by: renuka