This change completely removes the LIB_ALIAS design pattern an replaces
it by allowing LIB_PART objects to inherit from other LIB_PART objects.
The initial implementation only allows for single inheritance and only
supports the mandatory fields in the derived part because that is all
that the current symbol library file format will support. Once the new
file format is implemented and saving to the old file format is deprecated,
more complex inheritance will be added. The LIB_ALIAS information saved
in the document files was move into the LIB_PART object. This change
impacts virtually every part of the schematic and symbol library editor
code so this commit message is woefully incomplete.
REMOVE: Removed the symbol aliases concept from the schematic and symbol
editors and the symbol viewer.
NEW: Replace the symbol alias concept with simple inheritance that allows
a library symbol to be derived from another library symbol.
Fix highlight not cleared by Pcbnew.
Fix highlight not cleared by Cvpcb (missing code).
Add comments. Remove a few now useless printf used for debug
When clicking on a empty area, clear any highligthed symbols
Fixes: lp:1809977
https://bugs.launchpad.net/kicad/+bug/1809977
This makes using Scrollbars more easy to use, especially for "small" page sizes like A or B.
Note also the working/drawing area size is bigger than the page size (3 times)