This means unit tests won't run with the Build action, but they still will with the explicit Test action. This is for the best, because breakpoints only work when using the latter.

Reported in github/ReactiveCocoa#139.

Add armv7s as a valid architecture

Otherwise, apparently constant variables sometimes get clobbered (and thus rendered unusable by unit tests)

Enable Objective-C exceptions in the config file (just so it doesn't have to be set at the project level -- the fewer project settings, the better)