rs485echo: Add TX_ONLY mode and allow to repeat forever (!238) · Merge requests · SECO Northern Europe / Tools / gf-emc-test-suite · GitLab

'-z' for tx_only mode (yes, we are running out of useful chars...)
'-r' for repitition now understands '0', to not stop after a counted number of cycles.
Sort the parameters and help, some whitespace cleanups.