Add required library symbols to new file formatter and parser when copying
schematic symbols to prevent missing library symbol when pasting into a
different schematic which may not have the same library symbol available.
Fix a minor bug where the default schematic symbol reference was not set
by the parser when loading.
Fixes https://gitlab.com/kicad/code/kicad/issues/4442
Roberto Fernandez Bautista
Jeff Young
Wayne Stambaugh