misc...
* fix: select inside and touching: ignored ANY filters and hiding, and region
* fix: M3 tex paint/grab ignored _hidden_ models
* fix: M3 tex paint/grab ignored group ent (world, triggers, et cetera), model filters
* fix: shift+a by tex: ignored group ent (world, triggers, et cetera) filters
* fix: tex find/replace: ignored any filters, regioning & hiding
* fix: shift+a by classname: ignored filters, hiding, region
* fix: floor walker ignored group ent filters
* fix: csg subtract ignored group ent filters
* fix: invert selection: ignored group ent filters
* fix: tex find/replace: 'select by shader' mode for patches (was replacing with notex instead)
* fix: select inside and touching: were selecting group ents, as single unit (=sensitive to parent node and its bbox)
* fix: csg merge two group ents = empty group ent
* fix: csg subtract group ent completely = empty group ent
* fix: hollow group ent: could produce empty group ent
* func_groups are filtered by world filter only, not entities one
* new func_group filter, filterBar button; Rightclick = create func_group
