Updated Xcode project

[tiennou]

This also corrects what's stated in #323.

I uniformized the build settings, so that they flow from Project settings to Target settings.

Differences :

• The Development builds build for $(NATIVE_ARCH), aren't optimized, have Fix & Continue, Generate Debug Symbols
  
• The Release builds are Universal, are optimized (-Os), don't allow Fix & Continue, don't have debug symbols
  
• Both handle ObjC exceptions, no prebinding.
  

And now you can tweak a thing in libT, and get a Transmission.app that really links in you changes ;-)

[tiennou]

Bad One !

[livings124]

added in [3030]

[laurris]

Thanks, it's cleaner like this. Laurris (#323 author).