Create Makefile for buildbot CI.

* Configures Riak 2.0 with search enabled and LevelDB backend, plus  the included security stuff in src/test/resources.
* Runs the tests with all features except security, then turns security on and tests again.
* Includes a 'lint' task that could be used in the future for checking style and other non-functional things. Other clients (e.g. Python, Erlang) may use this for analysis tools (e.g. PEP8, dialyzer).

There is a forthcoming PR on basho/basho_buildbot for this.