Add GLOBAL -> SLIM transpiler

[Manuel Mujica]

If you use the current version on the slim branch, the global will be transpiled to amd then to slim; you'd get something like this:

which won't work.

[Matthew Phillips]

The only reason the current global format is that gross is to support this style of global:

var MooTools = {};

Yep, it's for mootools. In transpile@2 we'll drop support for that. However, since slim is a new format we don't need to support it at all there.

So the way to do a global would be to inline the code directly in that function; that's it.

[Manuel Mujica]

#88 (comment)