Carthage support

[tychota]

Hello @GeekTree0101

I'm using Carthage on my project (for build performance reasons).
I noticed that while both RxSwift and Texture are supporting Carthage, RxCocoa-Texture isn't.

Would it be a good fit for this project? (I'm going to add support on my fork anyway but if it interests you I can upstream it).

[tychota]

The commit is here: tychota@fced3ca

It is my first Carthage packet so some good practice aren't done. I'm going to test on my app and report if everything ok.