Shutter opening lag on light sources.

[iandobbie]

There are timing lags to allow for stage movement, SLM switching etc, however despite me thinking there was such a thing for years there does not appear to be a mechanism for shutter opening lag. We have a system with a 2ms lag between the digital pulse and light from the laser due to the DPSS laser needing a physical shutter.

I propose we add a setting to lightsource allowing a defined lag for shutter opening and closing to ensure the cameras is only trigger when light is present but we minimise the parasitic illumination. The opening and closing delay should be separately specifiable as they opening and closing lag may be different.