Add in methods for adding and removing flapper digits on the fly

[jeremysawesome]

@jayKayEss - I found myself needing to add/remove digits to the flapper on the fly. So I've modified the original code to allow for adding/removing digits.

Notable Changes:

• existing flappers are stored in a flappers object
• ids are added to flapper elements (so that the existing flapper object can be recovered).
• the .flapper() jQuery method now supports passing in a string or an object. (so that the specified action will be performed)
• the following methods were added to the prototype: addDigit, removeDigit, performAction

Let me know what you think!

[jayKayEss]

Hey @jeremysawesome looks pretty good! Do you mind updating the docs, too (so I don't have to :D) Thanks.