Make SpyDrNet TMR internals more generic

[jacobdbrown4]

This stems from SpyDrNet Issue #185 . Like SpyDrNet, SpyDrNet TMR has mainly been used for EDIF netlists. Because of this, some functions don't operate correctly on Verilog/EBLIF netlists. Once SpyDrNet's internals are made generic (in the near or distant future), some of SpyDrNet TMR will need to do the same.

Some things that only work for EDIF netlists:
uniquify_nmr_property
find_after_ff_voter_points