more work on wbs_export.py:
more work on wbs_export.py:

- added helpers: _addr_name, _sig_name, _reg_name, _format_mask, _mask_from_pos
- imported Signal
- iter_notify_port now yields a tuple
- added implementation for TPL_REG_WR

nussbrot/code-exchange,nussbrot/code-exchange,nussbrot/code-exchange,nussbrot/code-exchange