PATCH: twain -> sane/gphoto split [0/3]

[Marcus Meissner]

Hi,

Again the twain_32 -> sane.ds/gphoto2.ds split.

This splits the twain_32 which contained both datasourcemanager (DSM)
and a sane based datasource (DS) into:

- DSM code in twain_32

- DS code in sub drivers
	- sane.ds	- existing sane implementation.
	- gphoto2.ds	- new libgphoto2 import implementation.

- twain_32 itself no longer knows about sane or gphoto and is not
  linked against them anymore.

- twain_32 itself is able to use native drivers (detection is not done,
  but is only: find . -name *.ds | load)

Changes to previous submit after review from Alexandre:
- rc files in dlls/sane.ds/ renamed from twain_Xx.rc to sane_Xx.rc. 
- dlls/*/twain.h moved to toplevel include/, no longer triplicated

Also:
- Some fixes from Aric for the GUI code of the gphoto2 importer.
- ds_audio.c removed from sane and gphoto driver, since only stubs in there
  and audio not likely to be used anyway.

Ciao, Marcus