Adapt to new version conv-common-gw module
As part of resolving issue #1355, the conv-common-gw module has been modified so as to deal with the new inv ttl pulse LEDs on the front module of the conv-ttl-blo board.
Currently the conv-ttl-rs485 already implements the logic to drive the inv-ttl LEDs, however this code is located inside the conv-ttl-rs485 module, NOT in the conv-common-gw.
By resolving issue # and #1355, this is now a feature that is common to both boards. For the sake of consistency, the inv channels pulse LED logic should be placed inside the common gateware module, the same as it is currently done for the TTL channels.
This also affects the I/O for the inverter channels, currently the Top module of both boards copies directly from input to output. The new version of conv-common-gw module will deal with this repetition, again for consistency with how the blo and ttl channels are processed.