added the waffle.io badge

don't know yet if this will be really useful, but let's give it a try :)
[#59] Factorized the `collide` and `collideType` functions, added recursive search, and moved them into `EntityContainer`

while waiting for ticket #103 :)
[#59] renamed `me.game.container` to 'me.game.world', that makes it easier to understand than 'container' !

(we might as well deprecate a few function and encourage to use the
function under me.game.world ? )
[#108] directly query information from `me.game.world`
[#59] documentation update/fix
Programmatically draw the logo, instead of using an image for it