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.
Note that since the markup might exist for other reasons, it has
to be turned on with a preference setting. (It goes through a set
of bitflags so the same architecture can be used for other markup
structures that we might want to support in the future.)
Note also that this is more about engineering nomenclature than
visual formatting. In that respect it's more similar to overbar
than italic or bold.
In particular, don't move block back to start when duplicating,
and don't move crosshair back to start when doing a cut, copy, or
paste.
Also fixes undo for libEdit block duplicate.
Fixes: lp:1740138
* https://bugs.launchpad.net/kicad/+bug/1740138
1) when duplicating don’t keep original hidden until end of drag
2) reset selectionArea when showing it so it doesn’t flash in its previous location
3) center a pasted block on the cursor
4) don’t draw the source selectionArea when pasting a block
5) implement selection-style highlighting for contents of blocks
6) add pasted items to view so they don’t disappear when the block is placed
Fixes: lp:1747197
* https://bugs.launchpad.net/kicad/+bug/1747197