SQLite hotfix, queuing and amalgamation

* Added queuing to KIOEventStore to ensure that all SQLite calls are serialized
* Added sqlite-amalgamation-3080500 lib to eliminate dependency on libsqlite3.dylib, alleviates the "multiple copies of SQLite in the same project" issue moving forward
* Squashed an array allocation/deallocation bug in prepareJSONData that was screwing up API response data (see #26)
* Refactored semaphore in uploadWithFinishedBlock to call the main queue instead of blocking just in case the API doesn't respond
* Added kKeenSdkVersion to logging on KeenClient init