Carthage support

[joaopedrok]

I made a fork of your project to add support a carthage and i wanted to make a Pull Request to you but i was unable to do.

First of all i made a git clone --recursive because the project has a submodule that is URITemplate, but i couldn't even compile because the submodule doesn't have xcodeproj, so i can't integrate URITemplate with my project to even test if the support is working.

Do i need to do something?