Swift 2 and bug fixes

This release runs and compiles under the release version of Xcode 7, downloaded from the App Store.

Further modifications were made after integrating swix into another project. This release cleans up the code and removes or adds certain functions/operators. Specifically, it

• gets rid of the *! operator for scoping issues. Instead of A *! x, use A.dot(x).
• removes function find. The argwhere function is more clear what find/argwhere does.
• allows changing the seed for rand, etc
• removes swixUseCases and implements swix_ios_app
• updates image functions for Swift 2
• adds matrix.dot(ndarray).