kiji-express-music: EXP-420. Update to scala 2.10

issue: https://jira.kiji.org/browse/EXP-420
review: https://review.kiji.org/r/1695
commit: https://github.com/kijiproject/kiji-express-music/commit/3db51891f0d4e84866180fafff97bec9795c7e30
kiji-mapreduce: EXP-420. Update to scala 2.10

issue: https://jira.kiji.org/browse/EXP-420
review: https://review.kiji.org/r/1698
commit: https://github.com/kijiproject/kiji-mapreduce/commit/1ef695dc8dbe16f32e658570b30d8b36134b3eed