Improve dialog layout and fix UI policy issues with all of the dialog
boxes in the Gerbview and Pcbnew code paths.
Updated the use of component to footprint where appropriate.
(useful for boards having more than 2 layers)
Eeschema:fix compatibility with old schematic files, when they contain ERC markers.
Pcbnew: better test for allowed layers when creating/editing Dimensions and some other Graphic items
Drc: fix comments and messages for some drc tests.
Fix minor bugs in cleanup dialog options and plot solder mask function (thanks to Lorenzo to locate these bugs)
Pcbnew: better test for allowed layers when creating/editing Dimensions and some other Graphic items
Drc: fix comments and messages for some drc tests.
To do: fix issues in active layer selection when creating a track and layer pair selection dialog