@marius => englishification + dupe resources section

Will highlight the one sentence I still can't quite get my head around in the PR inline.
>* With **Swift**: they are like Clang Modules, but also …

This sentence makes like this not really sense to me anymore. Umbrella Headers are a part of Clang Modules. Perhaps we should just write:

>they are the bridging header for the framework module

And add:

>which essentially means that all Objective-C code you're interfacing from Swift within your framework has to be part of it's public API