Previously, bus elements that were not instantiated as individual nets
could not connect to each other. This caused issues for complex
schematics where busses needed to connect to other busses with elements
that resolved to the same net names. Functionally, this means mixing
bus elements, which we will replace with first-class elements in version
8 but currently can only be accomplished either by using bus aliases and
this patch or by individually instantiating each bus element as a
local label
Fixes https://gitlab.com/kicad/code/kicad/issues/14300
Fixes#12580
Additionally does not export no_connect netlist annotation on pins
which are both connected to another pin and a NC item, unless all
connected pins are stacked at the symbol level.
Adds testing of pin types to netlist QA unit tests.
Same pin name != same net name unless the pins are explicitly connected
Also add pin number to all unconnected pads ensuring they have unique
nets
Fixes https://gitlab.com/kicad/code/kicad/issues/13236
Seth Hillbrand
JamesJCode
Mike Williams
Jeff Young
Roberto Fernandez Bautista
Sylwester Kocjan