Clean up the code

[daniel-abramov]

I've noticed several problems when worked with the code:

1. Some inconsistencies in coding style: the order of use statements varies between files (it would be better to use the same style / order everywhere; one of the possible styles).
2. When multiple functions/structures/types are imported from the module, both use something::{str1, test, example} and use something::{ str1, test, example } styles are used, it would be nice to stick to one of the versions.
3. Sometimes the text width is more than 100 characters.
4. There is a lot of boilerplate code in each module when it comes to TCFType trait implementation. I think it makes sense to use impl_TCFType! macro from core-foundation-sys or something similar.

[nox]

We should probably use @sfackler's foreign-types crate.