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.
Allow trim netlist to be used for delay and functional simulation.
Each class implements a "trim_insts" set of instances that can be removed.
By default far left, right, top and bottom cells in the bitcell arrays are kept.
Use lvs option in sp_write
Fix lvs option in sram.