New version of Lightroom import using fixed and stable iop.

The new version does not use the current iop but one that is stable.
The structs and corresponding versions have been copied into lightroom.c
and the iop parameters are now just inserted into the database.

At then end we reload the new history from the database. At this point
Darktable will convert old iop parameters using the standard circuitry.
(legacy_params).

This will make the lightroom import module less intrusive and will
then require less maintenance work.
Revert "Move bilat definitions to header file."

This reverts commit 93293d84d2a267bf79c85d3fdb7dfd38ff8bb6fa.
Revert "Move splittoning definitions to header file."

This reverts commit 57524ac500306c972a368ef6ffa2bdbb09a825c0.
Revert "expose the dt_iop_clipping_params_t struct."

This reverts commit 5f5f2d7deccfeced6a05debe935ceb6799f367f5.
Revert "Add support for spots Lr import."

This reverts commit 3d8a0714c14a844b506946ea746ee867474b23f9.

Only parts:
    src/iop/spots.h
    src/iop/spots.c
Revert part of "Move colorzones definitions to header file."

Keep the new colorzones definition.
Revert "Add support for vignette Lr import."

This reverts commit bd5e29ebdc5c6ce8f8d6a8de4ab93eae0abe1778.

Only parts:
	src/iop/vignette.h
	src/iop/vignette.c
Merge branch 'po/lr-import'

* po/lr-import:
  Revert "Add support for vignette Lr import."
  Revert part of "Move colorzones definitions to header file."
  Revert "Add support for spots Lr import."
  Revert "expose the dt_iop_clipping_params_t struct."
  Revert "Move splittoning definitions to header file."
  Revert "Move bilat definitions to header file."
  New version of Lightroom import using fixed and stable iop.