API: simplify code: merge @werdmann's daq functions which allow to skip
DUT programming with the regular ones: it's the same code, just with
additional parameters (buffer size to be allocated, and init flag).
Do not use these functions unless you knwo what you do!
API/daqStart: add additional safety check for requested buffer size,
also store the requested buffer size in the member variable, so that
the fill status is computed correctly (was not the case before)