Compiled in hard-mode

The changes in this are pretty simple and don't alter the implementation.

I put XCode in hard-mode and fixed all of the Clang errors I could find. I also added a .gitignore and removed user-specific data for XCode.

The only change which I think needs explanation is where I copy weak properties to local variables (i.e. strongDelegate). Clang throws a warning a if a weak property is referenced, claiming that the property "may be set to nil". It is suggested to overcome this by copying a weak property into a local variable, which by default has a strong reference.