kiji-model-repository: EXP-281.  Update ModelRepo for new KijiInput/OutputSpec.

Fix model-environment JSON to match new KijiInputSpec, KijiOutputSpec
(changed as part of EXP-263).

Minor update to freshening code to use correct methods on new
AvroKijiSingleColumnOutputSpec.

Update pom.xml to use latest versions of express, modeling.

review: https://review.kiji.org/r/1329
issue: https://jira.kiji.org/EXP-281
commit: https://github.com/kijiproject/kiji-model-repository/commit/584ce0bdc069650b90fd0a837fe3c95f6dc6b878