Avoid unnecessary breakage due to blur before click

Hello FastClick developers,

While investigating the incompatibility between FastClick and recent versions of typeahead.js discussed in twitter/typeahead.js#792, I found that the source of the issue is FastClick's call to `blur()` before dispatching the synthetic click event which causes the `blur` event to fire before `click`.  This event order is not expected/supported by typeahead.js.  Although arguably this should be fixed by typeahead.js (too), since the event ordering is unnatural it seems likely that it will trip up other third-party code and therefore should be addressed in FastClick.

This PR doesn't completely fix the problem, but it limits the impact of the issue by only calling `blur()` on Android devices where it is required for proper focus behavior (as described in #24).  It could be further reduced to only the affected Android versions, but I don't currently have a suitable testing environment to determine which versions are affected.

Thanks for considering,
Kevin