2005-09-29  Sven Neumann  <sven@gimp.org>

	* app/base/tile-cache.c
	* app/base/tile-manager.c
	* app/base/tile-private.h
	* app/base/tile-swap.c
	* app/base/tile.c: keep the data size of a tile in the Tile struct
	instead of recalculating it over and over again. Adds an overhead
	of 4 bytes per tile but speeds up the tile cache significantly.