Feature/score format

* Removed scar tissue
* Added default string encoding in constants
* Added parameter checking
* Test case for POST with invalid parameter
* Redefined CONSTANTS as DATA_BLOB
* Mocked service for urlfetch
* Moved ScoreFactory to Score package
* Added GameTag to DB model
* DB Model now has default values
* Included FormatMapper in the score formatting chain
* Added default values for score formatting
* Implemented Formatters for ScoreSource
* Implemented Formatter for score data