Fixes https://gitlab.com/kicad/code/kicad/-/issues/8522
Conservative makes SMAA usable in Eeschema through weaker AA.
Aggressive reduces some artifacts compared to the High preset.
Restores the unused Ultra preset in the shader source to its original state.
This update replaces the existing uses of unique pointer creation with
the C++14 std::make_unique call that provides proper memory release in
event of an exception.
- support for background color setting
- removed several global config settings (such as g_Drc_On)
- wrapped most of global config settings in PCB_GENERAL_SETTINGS class
- reorganized PCB general options dialog to clearly mark which options concern only the legacy canvas
- new GAL feature for legacy users: double-click (or E) to change track width available as an option.
Fixes: lp:1530543
* https://bugs.launchpad.net/kicad/+bug/1530543
Fixes: lp:1707145
* https://bugs.launchpad.net/kicad/+bug/1707145