Firefox has a Object.prototype.watch method
Merge pull request #2274 from yohanboniface/watch

Firefox has a Object.prototype.watch method
minor code readability fix
revert commenting out watch for terser code #2274
Change touch detection check for ontouchstart in window like modernizr does. Fixes chrome touch emulation. Fixes #2277
call addLayers after initHooks where anim is detected, fixes #2281
fix FeatureGroup getBounds
fix Map hasLayer
fix LayerGroup hasLayer
fix build
fix old IE and stricter jshinting
Fix build
Add hasLayer tests
Make GridLayer methods safe to call pre-setView
bring this._map check back
add {r} format to url, which returns @2x when retina detected and enabled
fix retina condition
Make options object prototype-inherited

Fixes #2294
Use L.Util.create for class extension
Adding Leaflet logo in svg format