Add xccheckout.
Add workspace.
Rename Mac target and product.
Add iOS targets.
Import Foundation instead of Cocoa or UIKit.
Add Quick/Quick as a submodule.
Add Quick/Nimble as a submodule.
Add Quick and Nimble to workspace & test targets.

* Make the schemes shared.
* Replace placeholder test file.
* Clean up framework search paths for test targets.
Add Travis config.