New import (and export) mechanism

I've started writing a new import mechanism for .soy files, replacing the old soy.transports module with a importer that allows .soy files to be loaded as modules with the standard Python import command.

With the old method, "transport" objects acted as dicts of objects in the .soy files and could be loaded and saved as such. The resulting code looked like this:
import soy
MyGame = soy.transports.File('data/MyGame.soy')
window = MyGame['window']
redblock = MyGame['redblock']
(etc)

Now, the new .soy importer is added to sys.path_hooks when PySoy is first initialized and applys to any directory added after. When finished, the above code could be rewritten as:
import soy
sys.path.append('data/')
import MyGame


No "etc" needed because in that one import command data/MyGame.soy is loaded and made available directly in a module called MyGame. Much more pythonic, IMHO.

A separate class will be written next called soy.Exporter which PySoy objects can be added and removed from, then saved to a file such as this example which modifies the previously imported MyGame module:
archive = soy.Exporter(MyGame)
archive.grasstex = grass_texture
del(archive.bricktex)
archive('data/MyGame2.soy')


Similarly, two archives could be combined like this:
archive = soy.Exporter(MyGame)
archive2 = soy.Exporter(CharacterFoo)
archive += archive2
archive('data/MyGame3.soy')


The reasoning behind this is in most cases .soy files will be written by GIMP or Blender, so the most common use case for the soy.Exporter class is for combining and pruning the .soy files created by these tools.

As always, constructive/critical feedback welcome and appreciated.