ref: Event listener improvements and cleanup

[CatchABus]

This PR does few things based on event listeners.
More specifically:

• Added support for adding event listeners in XML
• Added descriptive on() call types for each event name
• Replaced notify calls with existing sendEvent method
• Removed unneeded hasListeners calls
• Added generic type for data argument to sendEvent method
• Fixed in issue that caused mapInteraction event data payload to be inconsistent between the two platforms
• Replaced ClickType structures with a pure ClickType enum
• Click event clickType will now return an integer for both platforms which can be compared with new enum values (this required an additional JNI call of swigValue() on android)

[farfromrefug]

@CatchABus very nice looks good to me!
BTW to make a new release i need to figure out how to "release" the native side, or more precisely how to make gradle/pod use my releases on github. master is now based on my fork of the carto SDK so we should not use old releases from carto