Add protocol buffer query service at parity with Riak Search and corrosponding r_t
Expand test to include params and unicode, make pb service safer in the face of unforseen errors
Fix list encoding to allow lists of strings, fix tests
Add multi-value field support

* Instead of concatenating multi-valued fields into one binary add a
  `{FieldName, FieldVal}` pair to the result for each value.

* Add a test for multi-valued fields.

* Log the stacktrace for an unknown error.
Merge branch 'er-pbsupport'

Conflicts:
	src/yz_app.erl

Had to move the PB register call into `maybe_setup`.
Enable yokozuna for all tests