kiji-scoring: POM-40. Require JDK 7 to compile Kiji projects

issue: https://jira.kiji.org/browse/POM-40
review: https://review.kiji.org/r/2027
commit: https://github.com/kijiproject/kiji-scoring/commit/b9a2e673ca90cab72d30958539b55226cbb73873
kiji-music: POM-40. Require JDK 7 to compile Kiji projects

issue: https://jira.kiji.org/browse/POM-40
review: https://review.kiji.org/r/2021
commit: https://github.com/kijiproject/kiji-music/commit/cded839bd3922c19ad6c51c4affce4c23e049569