export Tucam trigger mode and trigger edge

The camera supports as default mode a roller shutter and can be switch to global mode or synchronous mode. In addition the input trigger can be detected on rising or falling edge.

• Few fixes as well, the pixelsize in meter now, the firmware version is a string.
• Manage the cold start and take a fake acquisition, otherwise the detector does not start on the first trigger.
• set the trigger mode in prepareAcq()