Use a single injection order file

I was originally saving all injection orders to a directory under their hash. That's not required since I'm not requiring people to depend on this directly just yet.

If I require it for ClojureScript in the future I'll reinstate this feature.

Internal refactor and required namespaces

The munging code is a lot nicer now (I think?) and you can specify which namespaces specifically are required in the injected dependencies file to filter the list of files down.

This means unused namespaces won't be injected which is quite nice.

Initial release

Nothing special to see here, mainly extracting the existing munge code out of the Conjure repository into this hopefully slow moving repository.