Preliminary Riak support
Updated riak support
Improve Riak support
Add SQL to Riak converter
Add Riak backend to the testing suit
Fixate Riak client library
Improve Riak pool management
Fix case clause
Fix roster versioning support when Riak backend is enabled
Clear Riak data when initializing the testing suite
Improve test suite explanation
Don't forget to shutdown rooms before starting the testing suite
Make it possible to check Riak connection status
Check Riak connection before running the corresponding suite
Document Riak support
Add --enable-riak configure flag
Re-generate the configure script
Fix compile errors introduced by previous cherry picks