tomato driver for Bronkhorst flow and pressure controllers.

This driver is a wrapper around the bronkhorst-propar library. This driver is developed by the ConCat lab at TU Berlin.

• constant_pressure for pressure controllers only (0 in SENSOR_MAP)
• constant_flow for (mass) flow controllers (1 and 3 in SENSOR_MAP)

• setpoint for all devices, pint.Quantity(float, self.device_unit) within the capacity range of the device
• control_mode for all devices, dictates valve status, str from the MODE_MAP
• temperature optional - if available, RO, pint.Quantity(float, "celsius")

• Peter Kraus
• Alexandre Gbocho