Made Frameworks an aggregate project for GNUstep, removed default...

Commit by leighsmith :: r3444 /trunk/MusicKit/Frameworks/ (18 files in 5 dirs): (link) Made Frameworks an aggregate project for GNUstep, removed default GNUSTEP_INSTALLATION_DOMAIN for frameworks to help in single build process, (should be passed on the command line anyway), cleaned up code causing warnings on gcc 4.3 due to untyped return of nil and other cavilier treatment of types