2008-10-09  Michael Natterer  <mitch@gimp.org>

	Bug 134956 – Curves tool doesn't save free curves

	* app/core/gimpmarshal.list
	* app/widgets/gimpsettingsbox.[ch]: add signal "file-dialog-setup"
	and emit it when the export/import file chooser is fully
	constructed. Callbacks can then do additional things to the
	dialog, like adding custom buttons.

	* app/tools/gimpcurvestool.h
	* app/tools/gimplevelstool.h: add boolean member
	"export_old_format".

	* app/tools/gimpcurvestool.c
	* app/tools/gimplevelstool.c (gimp_*_tool_dialog): connect to
	the settings box' "file-dialog-setup".

	(gimp_*_tool_export_setup): new callback which adds a toggle to
	the file choosers that allows to export to the old format.
	Default saving the new format, we defaulted to the old one before.

	(gimp_*_tool_settings_export): check the "export_old_format"
	boolean and only save the cruft format if it is TRUE; chain up
	otherwise, which generically saves the new format.

	* app/tools/gimplevelstool.c (gimp_levels_tool_settings_import):
	add the same file format detection code as in the curves tool
	so it transparently loads old and new levels files.


svn path=/trunk/; revision=27194