Session Guard Integration Test for CPP-161

* Added a testing directive preprocessor definition
  * This is currently used for the session to throw an exception instead of abort during the session guard and for the ref counter in the event of a double free
  * CMake option CASS_USE_TESTING_DIRECTIVE is required and is only available if CASS_BUILD_TESTS is enabled
  * Updated the integration tests CMake configuration to include the LIBUV_INCLUDE_DIR for builds using the libs directory
* Updated CCM bridge to not use the -s (start after create) argument for some of the create methods to ensure wait for binary and wait for other notice (Cassandra is socket is available)
Agreed, the conditional compilation with the testing directive definition does lend itself to alter the core behavior and perform undefined behavior.

The patch looks good with one exception; the downgrade of Boost to v1.54: https://gist.github.com/aholmberg/d7a3dd7c21376350c4ee#file-gistfile1-txt-L27-L28.  This was changed by @mpenick during beta4: https://github.com/datastax/cpp-driver/commit/8873d41787caea1c7d725e61479ea7d7385b85f0#diff-af3b638bc2a3e6c650974192a53c7291R256.

Patch has been applied without the downgrade of Boost.