DDLSHELL-15 formatted row keys

Tested with mvn clean verify; new unit tests added
Also ran against an rc4 bento box; created, altered, described tables in kiji-schema-shell and accessed them through "bin/kiji"

These commits should be squashed and committed together with the message:
DDLSHELL-15. Add formatted (composite) key support to schema shell.

This is structured as a series of 5 commits that roughly do what the messages say.
* all TODO comment items were removed by the end of this process
* the DDL parser was updated a bit in commit #2 to use the THROUGH <lastHashedField> syntax
* Some silliness I added to FormattedKeyHashComponent to try to avoid a null ptr warning in findbugs got undone by the end of it and added to a findbugs exclude file, just like the others. I had forgotten that findbugs is much more false-positive-y on scala.

I will post a separate patch to the docs repo later today with new documentation updates.