EXP-121. Add the prepare phase to model definitions.

issue: https://jira.kiji.org/browse/EXP-121
review: https://review.kiji.org/r/851
EXP-162. Make use of avro and scala specific classes in model config consistent

issue: https://jira.kiji.org/browse/EXP-162
review: https://review.kiji.org/r/868
EXP-170. Upgrade to use latest root-pom and KijiMR releases.

This commit updates the pom of the project to depend on the latest
root-pom release (1.1.2) and the latest KijiMR release (1.0.2).

Reviewed by: renuka