* generator/BoxedGen.cs : New boxed type generatable.
* generator/ObjectGen.cs : Add boxed type property generation and stub
off interface properties for now.
* generator/Parser.cs : Add boxed element parsing.
* generator/SymbolTable.cs : Add IsBoxed and IsInterface methods.
* glib/Boxed.cs : New base class for deriving boxed types.
* glib/Object.cs : Add boxed GetProp/SetProp methods.
* parser/gapi2xml.pl : Add boxed type element formatting.
* parser/gapi_pp.pl : Add preprocessing of the generated sourcefiles.
Handle the builtins and make them identifiable to the xml generator.
svn path=/trunk/gtk-sharp/; revision=2012
