LAYER_VIAS needs to get set for them to print at all, and GetLOD
needs too look at the view layer visibiilties, not the board layer
visibilities.
Also implements a more pad-like strategy for printing blind/buried
vias when printing one layer per page (where the top/bottom arcs
don't make sense).
Fixes https://gitlab.com/kicad/code/kicad/issues/1938
CHANGED: Settings are now stored in versioned sub-directories
ADDED: First-run dialog for migrating settings from a previous version
CHANGED: Settings are now stored as JSON files instead of wxConfig-style INI files
CHANGED: Color settings are now all stored in a separate settings file
CHANGED: The symbol editor and footprint editor now have their own settings files
CHANGED: Color settings are no longer exposed through BOARD object
CHANGED: Page layout editor now uses Eeschema's color scheme
Settings are now managed through a central SETTINGS_MANAGER held by PGM_BASE.
Existing settings will be migrated from the wxConfig format on first run of each application.
Per-application settings are now stored in one class for each application.
* Split up the thirdparty code into the thirdparty folder (#3637)
* Create a new kimath static library containing all the math functions
This is part of cleaning the build system for #1906.
Jeff Young
Jon Evans
Ian McInerney
Maciej Suminski