- added ability to turn off the outline plotting for Gerber objects (will speed up the plotting but the plotting visual quality will degrade); controlled from Preferences -> Gerber -> General
- plotting visuals in 3d graphic mode will no longer create some unnecessary lists
- in Excellon Editor made sure that the tool diameter is always updated before adding a new drill (or drill array)
- changing units is not possible while in Editors
- changing units outside the Preferences will make no permanent changes
- deleting all shapes from the shapes collection (OpenGl graphics) will reset also the index in the collection data dict
- fixed the Tcl Command AlignDrillGrid
- fixed the Tcl COmmand Panelize, Excellon panelization section
- Fixed an issue in Tool Calibration export_excellon method call
- PEP8 corrections all over the app
- modified the visibility change in Excellon UI to no longer do plot() when doing visibility toggle for one of the tools but only a visibility change in the shapes properties
- fixed the issue with factory_defaults being saved every time the app start
- fixed the preferences not being saved to a file when the Save button is pressed in Edit -> Preferences
- fixed and updated the Transform Tools in the Editors
