Copy Shared Schemes During CI Build

Ever since I started adding shared schemes to my projects for use in Travis I have been annoyed by the modifications to the schemes. If you use the Xcode UI for selectively enabling/disabling tests, then you wind up with local modifications to the shared schemes that you need to reset or ignore. It's bothersome and eventually someone will commit a change that disables part of the suite.

This pull request updates the Travis configuration so that we keep a copy of the shared schemes in the Tests/Schemes directory and copy them in during CI builds. This avoids the aforementioned noise during normal development.