Don't block other click handlers

This keeps Tappy from preventing other click handlers that might be bound to something. On a current project, for example, we have an analytics script that attaches a click handler to any element with a certain class. Tappy was preventing that click handler from being called.

This change makes `trigger` trigger a `click` event, but passes an extra argument that `end` then checks for, so that it doesn't get stuck in a loop. The current implementation is a little greasy, and could probably use a some refactoring to be clearer as to the function of passing `false` around.