Update gitignore for Mac development.
Update the Ios project to be similar to WinPRT.

Added and removed file references so they are the same as Csla.WinPRT.
Deleted files not used
Fix "The modifier `async' is not valid for this item" compile error

The compiler had issues when trying to add async to the ISavable
methods:
- Task<object> SaveAsync()
- Task<object> SaveAsync(bool forceUpdate)

The easiest solution is remove them and rely on the ISavable<T> methods.
Do not use Dynamic methods for IOS

Linq in IOS is limited and was missing some of the Linq methods.  This
prevents the usage of Dynamic methods.  The solution was to use the
same code for Csla.WinPRT before it was updated to use Dynamic methods.