Add interface sorting support.

[dgjustice]

@qduk I have refactored the gist I sent (thank you for pointing out how broken that was! 😬). I finally put together a proper PR with all the test cases I could find. This is a bit more complexity, but taking the "character class" approach allows future modifications to completely customize the sorting logic based on arbitrary groups of characters. Sorts happen first by CharacterClass.weight, and secondly by whatever logic you like, for example, casting to int for the CCInt class.

[qduk]

@dgjustice gotta say, this is pretty awesome stuff. I've just got one other note.

Docs is picking up on your character classes and helper functions. I personally don't think those need to be in there. I am able to get them undocumented by making them private functions. I'll defer to @itdependsnetworks and @jeffkala to see if they agree or not.

Thanks again @dgjustice. Once this is merged it'll allow me to build out my PR.

[jeffkala]

@dgjustice gotta say, this is pretty awesome stuff. I've just got one other note.

Docs is picking up on your character classes and helper functions. I personally don't think those need to be in there. I am able to get them undocumented by making them private functions. I'll defer to @itdependsnetworks and @jeffkala to see if they agree or not.

Thanks again @dgjustice. Once this is merged it'll allow me to build out my PR.

I can't say I have a huge issue either way on whether those show up in the docs. To me more is always better in docs, but I understand the concern.

[jeffkala]

This is an awesome addition. Learned a ton just from reading over the code. Thanks @dgjustice

[dgjustice]

Travis is being flaky again. I think the last commit is clean (passes tests); the build failed on installing dependencies.

[qduk]

@jeffkala You make a good point. Never hurts to have the extra documentation.
@dgjustice Thanks for adding the docstring example.