Potential breaking changes introduced. Spelling fix + added Cordova

If you used any constant with related to 'MESSANGER' - fix to 'MESSANGER'.
Also anyone that used the plug-in within Ionic / Cordova / whatever.... notice the new change that will NOT detect 'Safari' as browser when 'Cordova/#.#.#' is added to UA via the Ionic/Cordova framework. It will instead detect CORDOVA as browser.