Improved the route horizontal and vertical pin functions to
create a single pin at the end.
Swapped A and B on wordline driver input for cleaner routing
in most technologies.
Fixed vertical supply routing in port_address.
Add hard decoder gates (nand, inv, pnan)
Add conditions for routing using LI layer in s8.
Generalize bus layers for decoders.
Move custom cells to own directory.
Fixed via directions, etc.
Add 4x16 hierarchical decoder and test case