Started tiles rework
Removed the default minZoom and maxZoom because they override the maxZoom of the individual tileLayers
Reworked tiles attribute, now it observers for the full "tiles" object, and creates a new tileLayer if the tiles options change
Solved a bug on the geojson property (after a geojson removal) and on tiles property
Merge branch 'tiles'

Conflicts:
	dist/angular-leaflet-directive.min.js