Add support for multiple gestures of the same type with different parameters

I'm having a hard time adding two separate `:tap` gestures to my view.
The goal is to trigger different actions if the view was tapped with one or two fingers.
I know in pure Cocoa-Touch this is possible by adding different recognizers and making use of `requestRecognizerToFail()` to differentiate.

I think there should be a way in RMQ to do this:

``` ruby
rmq.on(:tap, fingers_required: 1) { |sender, event| puts "one finger tap" }
rmq.on(:tap, fingers_required: 2, taps_required: 2) { |sender, event| puts "two finger double tap" }
```

No file or test is named. Start by tracing the `rmq.on` gesture registration path and compare the requested behavior with Cocoa-Touch recognizers and `requestRecognizerToFail()`. Done means separate `:tap` handlers can use `fingers_required` and `taps_required` so one-finger and two-finger double-tap actions trigger independently.

Written by the indexing model from the issue text.