driver andorcam3: improve log messages
driver semcomedi: simplify set_to_resting_position

no need for a timed command, just writting to both channels works fine and simplifies a lot the code.
driver semcomedi: remove unused code

was only used for testing during the early stages of the development
driver semcomedi: remove unused commented code

code was a previous version of the few lines following it.
driver semcomedi: change default values from scan() to something more reasonable
gui: remove InstrumentalImage

Finally. The new implementation using only DataArrays seems to work fine, so InstrumentalImage
has no usage anymore.