Backport release of the v5.0.0 symbol library for use with kicad vers…

…ion 4.0.x

Symbols released in conjunction with KiCad 5.0.0

Symbols intented for KiCad 5 release candidate 3

Backport release of the v5.0.0-rc2 symbol library for use with kicad …

…version 4.0.x

Symbols intented for KiCad 5 release candidate 2

Symbol library for KiCad version 5.0.0 release candidate 1