Wrap ChamplainErrorTileRenderer

	* champlain/champlainmm.h: Add error-tile-renderer.h.
	* champlain/champlainmm/.gitignore: Ignore
	error-tile-renderer.*.
	* champlain/src/champlain_signals.defs: Add "tile-size"
	property.
	* champlain/src/filelist.am: Add error-tile-renderer.hg.
	* champlain/src/error-tile-renderer.[hg|ccg]: New files.
	* tools/extradefs/generate_extra_defs_libchamplain.cc: Add
	CHAMPLAIN_TYPE_ERROR_TILE_RENDERER.