Eeschema plot: fix Bug #1391538 (eeschema PS/PDF export, objects have wrong Z-order )
Cvpcb: fix bug Bug #1386933 (Horizontal scrollbars not appearing in CvPcb)
bitmap2component: Add a layer selection to export a logo for Pcbnew from a Cirilo Bernardo's patch.
Apply patch from Cirilo Bernardo with some minor changes: mainly allows also the solder mask layer and keep ref and value fields on the silk layer.
Polygon tools: update Clipper lib to 6.2.1 
Minor doc update.
Improve MsgPanelInfo for line segments in the module editor
Factor out some common code in hotkeys_module_editor.cpp
Add EDGE_MODULE::RotateAboutOwnCenter() function
Make a start on exact moving
Add hotkey for move exactly
Extend move exactly to other types

Also add specific drawsegment centre-finding and rotation code.
Integrate block move exact and footpritn move exact
Fix whitespace
Duplicate hotkey - only works for pads
Duplicate for pads, text and edges, still need to do block
Allow move exact while duplicating
Fix block move exact menu wording