Must set PYTHONPATH to include OPENRAM_HOME now.
Reorganizes subdirs as packages.
Rewrites unit tests to use packages.
Update README.md with instructions, dependencies etc.
Update sky130 module imports.
Change tech specific package from modules to custom.
Changes to allow decoder height to be a 2x multiple of bitcell height.
Split of control logic tests.
Fixed track spacing in SRAM and channel router
PEP8 cleanup.
this is the first step to allow engineers, porting technologies, more room
for routing their handmade cells.
For now, we don't allow the specification of power_grids where the lower layer
prefers to be routed vertically. This is due to the router not
connecting some pins properly in that case.
Signed-off-by: Bastian Koppelmann <kbastian@mail.uni-paderborn.de>