some style cleanup

and displayBase

Building up a better execute harness
* utilizes composable options from firrtl
* Add IO() wrapping and compile with StrictOptions.

change signal name for verilator 3.886

create temp directory to prevent thread unsaftety

flush vpd every cycle for debugging

signal names start with its top module name, not with 'v'

Add method to obtain main_time and define function sc_time_stamp() - …

Although this is only required if we emit something requiring a time stamp, we may as well do it all the time. Determining when it would be required could be problematic, and we should minimize differences in generated emulations.