Includes improvements to Update PCB from Schematic dialog and
corresponding changes to Symbol Properties, Sheet Properties and
Footprint Properties.
Fixes https://gitlab.com/kicad/code/kicad/issues/4012
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.
Drop all uses of wxRAISED_BORDER and wxSUNKEN_BORDER from dialogs and
panels used in main frame windows.
Drop use of wxSP_3DSASH options on all wxSplitterWindow definitions.
Minor dialog alignment and spacing fixes.