Fixes a crash when typing fast in the place footprint filter box.
Also adds a bunch more checking to GAL locking, including making
sure the same person unlocks as locked, and preventing piece-meal
calls (the RAII objects must be used).
This prevents deadlocks when exceptions are thrown and the context
ends up not getting unlocked.
It also removes an earlier hack to try and minimize this which
didn't work anyway.
This tool is currently very rudimentary. I pushed it because I need to
collect responses from it from users with diverse graphics
configurations, so I want the tool to be in the nightly builds.
This affects no KiCad code.
Jeff Young
Mathias Grimmberger
Simon Richter
Chris Pavlina