Disable the text update event for the orientation cutom value field before
updating it when the radio buttons are selected. This allows to use the
conventional EVT_TEXT handler, rather than KEYDOWN, which has two effects:
* Tabbing though the dialog no longer sets custom orientation
* Click-driven clipboard actions trigger the update correctly.
Introduce a helper function in validators.h to assist in updating
validated fields without triggering further events.
Fixes: lp:1819006
* https://bugs.launchpad.net/kicad/+bug/1819006
Auto-selecting of the first grid element is performed in the footprint
editor to facility rapid editing. Rapid editing of the 3d-model fields
is not as useful and requires multiple esc-keys to cancel. This limits
the auto-edit to only the reference tab.
Fixes: lp:1815456
* https://bugs.launchpad.net/kicad/+bug/1815456