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.
Replace all instances of "component" and "part" with "symbol" when
referring to schematic and library symbols.
Replace all instances of "component" with "footprint" when referring to
board and library footprints.
Minor dialog layout fixes to some of the dialogs impacted by the UI
string changes.
* Fix parent of elements in wxSizers.
* Update old dialog with recent version of wxFormBuilder.
* Add wxALIGN_CENTER_VERTICAL flag to some dialogs.
* Update wxFormBuilder timestamp in generated sources.
* Replace all occurrences of the word "part" with "unit" when referring to
multiple unit components for improved consistency.
* Replace "shared by" with "common to" when referring to objects (lines, arcs,
pins, etc.) that are common to all units.
* Improve wording in library component properties dialog.