Sdk, module and running configuration

Ok, this is a exciting and a rather large one :smiley: Everything has only been tested in OSX. It *might* work on Linux, and it will almost certainly *not* work on Windows (i.e. I haven't added the `.exe` extension in all the places we need. This should be easy to fix, anyway)

* You can now create a Rust SDK. To do so, specify the place where `rustc` lives. After that, `rustc --version` will be run, and after getting the host triple, I check on `../lib/<triple>/librust` for libraries, although I don't do anything with them yet.
* You can create a Rust module as well. There is no `right click -> New -> Rust` yet, but that's easy to add (I'll add it later). For now, use `New -> File` and use a `.rs` extension, although you probably know that already :smile:
* You can also create a run configuration (not a debug one for now). You *must* specify the "Main file" argument, and it will have to be something like "src/main.rs", i.e. the relative path to your main file from your module. The path will be colored red as if there were errors, I know. Also, clicking on the `...` button doesn't work yet.
* There is no way of compiling without running (Cmd+F9). If you try it, it will throw an error.
* When you try to run, a compilation will first start, and any errors (and probably warnings, although I haven't tested them yet) will show on your file. You can double click to go to the error, exactly like in Java. I love this part, and spent a lot of time to make it work :smiley: 

The code for compiling and running is a mess, unfortunately, as I copied large amounts of it from the Java  target (and some non-compiling parts from Go, they have an awesome IDEA plugin already). The problem is, some of it is from 2003, when the APIs were different/non-existent. Also, Java is very intertwined with a lot of things in IDEA. That means, I'm probably not using the best API to do all the compilation, and half of the code I added for it is not used, but is the best I can do for now.

This will probably need lots of QA and QR, so let me know of any problem you find.
We should probably start giving some though to code style. Its kind of ironic that the Intellij Community source has 'my' prefixed for class variables when it gives this information quite clearly through hilighting.