added mac and web support

hey there,

today we have added web and mac versions of our tweebly game.  
for a game, supposed to take only up to three minutes, 
downloading and installing a game of that duration before playing,
can be a barrier of entry and a bit tedious, so here we go!

sadly web only works for firefox and chrome atm, due to us needing to use a 
new-er version of unity's web gl support, that is not yet compatible with
all browsers.

our ultimate goal is of course, to get our launcher up and running,
to seamlessly integrate our tweebly things, into your games collection.

hope you enjoy, let us know if there are any bugs or mishaps.

your team tweeble.