Report run-time after placement.
Report starting bb-cost and % cost reduction
Add helper functions for net-files by namebase...

Add the following helper functions for dealing with net-files by namebase
_(i.e., `ex5p`, `tseng`, `clma`, etc.)_:

  * `get_net_filepath_by_namebase(namebase)`
  * `get_parser_by_namebase(namebase)`
  * `get_netfile_info(namebase)`