Create docs for creating build-time plugins

[unscriptable]

There are no docs for creating cram plugins. Need docs nao!

[briancavalier]

Yay docs!

[gogamoga]

point me in some direction

[unscriptable]

@gogamoga: look at the curl and wire plugins for some examples. :)

[unscriptable]

The basic idea is to create a simplified AMD define() that exports a value. The io object has some useful helper functions on it.

[gogamoga]

ok, going to try something. Have to do it in js instead of coffee :(