Revert "don't reset zoom when adding new instance"

This reverts commit f1364a91dbc9ab3e792c5dd529b46bd14310ba3d.

It introduced some breakage which still has to be fully sorted out.
lens correction: fix for #9270

offer the three photometric GUI controls also when automatic search
gives more than one hit. Just take the first one as we already do
for process().
cache: have full buffers according to potentially exporting  threads
pack blendif settings a little bit closer in GUI

that way color picker values can be actually read and
IMHO it's more aesthetically pleasing