Wrap ChamplainImageRenderer

	* champlain/champlainmm.h: Add image-renderer.h.
	* champlain/champlainmm/.gitignore: Ignore image-renderer.*.
	* champlain/src/filelist.am: Add image-renderer.hg.
	* champlain/src/image-renderer.[hg|ccg]: New files.
	* tools/extradefs/generate_extra_defs_libchamplain.cc: Add
	CHAMPLAIN_TYPE_IMAGE_RENDERER.