* generator/CallbackGen.cs : implement new IAccessor iface so that
callback fields on structs can now be accessed.
* generator/ClassBase.cs : remove/abstract some methods incorrectly
located here.
* generator/ClassGen.cs : implement methods previously inherited from
ClassBase incorrectly.
* generator/HandleBase.cs : new base class for native ptr wrappers.
Implements new IAccessor interface and code moved from ClassBase.
* generator/IAccessor.cs : new iface to generate field/prop accessors.
* generator/InterfaceGen.cs : derive from new ObjectBase.
* generator/LPGen.cs : implement IAccessor.
* generator/LPUGen.cs : implement IAccessor.
* generator/ObjectBase.cs : new base class for Object/Iface types.
* generator/ObjectGen.cs : derive from new ObjectBase.
* generator/OpaqueGen.cs : derive from HandleBase.
* generator/StructField.cs : refactor Generate method using new
IAccessor interface.
* */*.custom : add obsolete impls for some existing c_cased struct
field accessors that are now StudlyNamed.
svn path=/trunk/gtk-sharp/; revision=46878
