* glade-id-allocator.c, glade-id-allocator.h: Performed house cleaning.
          - Use g_slice_new where appropriate.
          - Hide private implementation details.
          - Added g_return_if_fail guards.
          
        * gladeui/glade-project.c: Use GladeIDAllocator for allocating unsaved numbers.

svn path=/trunk/; revision=1264