Harmonize coding style and whitespace
Update to ARC
Remove workaround for signatureWithObjCTypes:

This method was made available in 10.5 along with documentation.
Remove commented out code
Use Foundation (Core) data types
Reorganized Dialog.mm

Mainly ensure that the class implementation follows it's interface declaration.
Remove unneeded import of Carbon.h
Use new APIs for reading/writing plists

The previous APIs were deprecated because they do not follow proper Cocoa memory management rules.