* plug-ins/common/cartoon.c
* plug-ins/common/cubism.c
* plug-ins/common/displace.c
* plug-ins/common/dog.c
* plug-ins/common/emboss.c
* plug-ins/common/engrave.c
* plug-ins/common/gauss.c
* plug-ins/common/glasstile.c
* plug-ins/common/neon.c
* plug-ins/common/noisify.c
* plug-ins/common/oilify.c
* plug-ins/common/photocopy.c
* plug-ins/common/ripple.c
* plug-ins/common/sharpen.c
* plug-ins/common/shift.c
* plug-ins/common/sobel.c
* plug-ins/common/softglow.c
* plug-ins/common/spread.c
* plug-ins/common/tileit.c
* plug-ins/common/whirlpinch.c: make sure tile cache is allocated
before preview is shown -- significant speedup in some cases,
minimal in others.
* plug-ins/common/sel_gauss.c: give it a tile cache (didn't
have one). Still very slow but a little better.
b3eba64977