Make feature handler propagate touch events

This commit is a follow-up on issue #294 (commit a6119f6) and #861 (commit c7a4045). The feature handler should not stop the bubbling up of browser events. In this particular case, when the feature handler is activate, Sencha Touch will trigger longpress events when panning the map because the feature handler stops touchmove.
Merge pull request #955 from elemoine/stopevent

Make feature handler propagate touch events (p=@elemoine, r=@ahocevar)