SCHEMA-270. Cleanup in TestFormattedEntityId.

Signed-off-by: Aaron Kimball <aaron@wibidata.com>
SCHEMA-251. Document KijiTable.openTableWriter() and KijiTable.openTableReader().

Signed-off-by: Aaron Kimball <aaron@wibidata.com>
SCHEMA-106. Hide CellSpec constructor.
Change CellSpec target autience to Framework.
Update CellSpec javadoc.
Move CellSpec from o.k.s.layout.impl to o.k.s.layout.