kiji-schema: SCHEMA-606. Plug ColumnReaderSpec into KijiTableReader

issue: https://jira.kiji.org/browse/SCHEMA-606
review: https://review.kiji.org/r/1451
commit: https://github.com/kijiproject/kiji-schema/commit/9910fd0a13c69ffefe9acffdabc96bf61933097d