Added a multicamera upgrade for Hamamatsu cameras

[jeffmoffitt]

I revised my previous pull request to include the suggestions made.

In this version, properties of the camera triggering are set via values in the configuration XML.

[HazenBabcock]

Thanks for this.

• What are the default values for 'trigger_active' and 'trigger_polarity'?
• Is the default still that the camera is the trigger source? I assume that setups that are using a single camera without external triggering will still "just work"?

[jeffmoffitt]

The default value for trigger source is INTERNAL. So if the user does not specify a value in the configuration xml file, it will default to the behavior one would expect for a single camera system.

The default value for trigger_active is SYNCREADOUT. The default value for trigger_polarity is POSITIVE. These are the values that we prefer for our current multi-camera work.

If the trigger_source is INTERNAL, these values are ignored, so again these changes will not change the performance of single-camera setups that do not include these values in the configuration xml.

We have tested these changes with both a multi and single camera system, and they seem to be fine.

[HazenBabcock]

Great, thanks!