Use CI to build dynamic framework on pushed tags if tests succeed

[seivan]

Would require:

• Adding support for CI (Travis?)  #55
• Adding pre-built binaries as .zip files under Github Releases #54

I could implement this as I've done it in the past.
It would use Github releases to upload artefacts, in our case a YamlSwift_framework.zip attached to a tag. It would work with Carthage to get prebuilt binaries.

[behrang]

It is becoming your project now, so feel free to do anything you think would make this project better. I'll transfer it to you in a few days.

[seivan]

@behrang Please don't transfer it. It's fine where it is. I can't really help more than just touch things up and update Swift.

[behrang]

Ok, we'll keep it here for now.