adium: moving build vars to xcconfig files, including NSS as build dep

adium: moving build vars to xcconfig files, including NSS as build dep

Moving Xcode build variables into the xcconfig files so that
they can be tracked (and possibly generated by automake)

Added NSS as an external build system dependency, created
pre/post steps to fix install_name, and copy libs to our dir.

Minor modification to "Don't Publish" code to conform to Obj-C
var naming standard, and a slight visual change to prefs XIB.