Power straps bbox should be implemented

[harrisonliew]

hammer/src/hammer-vlsi/hammer_vlsi/hammer_vlsi_impl.py

Line 635 in 66b757e

# By default put straps everywhere

From debugging with @sohumdatta, you cannot implement power rings outside the core area using the straps API if this bbox is set as None (in the Innovus plugin, bbox = None causes straps to only appear in the core area, which prevents it from connecting to power rings).