acquisition: pl_exp_setup_cont

We must not use pl_exp_setup_seq since you cannot pass the whole memory to store all the frames, this is why you only start an acq. of one frame and restart the exposure inside the threadFunction() which is not good for hw synchro., instead one use pl_exp_setup_cont() where we can pass a short circular buffer of for instance 16 frames, and just stop the acquisition once all the frames have been acquired.

• in the threadFunction() there is no memcpy from your temp buffer to the lima buffer ????
• in the threadFunction you set the pl_exp_setup_seq acquisition trigger mode to a fix one, not using the mode set by the user

I propose:

• only use a circular temporary buffer of 16 frames and the continuous acquisition mode for both sequence and continuous acquisition (0 frame)
• move acquisition preparation code into prepareAcq if possible
• use ThreadCmd tool instead of a hand made thread and mutex mechanism