Partly buffered measurements

[THuckemann]

Plan is to have buffered measurements separated into smaller segments. After each segment break conditions can be checked.
Todo:

• Separate setpoints into the right segments based on max. voltage difference
• Include compensation sweeps
• Test compensated sweeps
• Include static gettable parameters
• Make sure that changing num_points is sufficient for all kind of buffered instruments (especially lock-ins)
• Include break conditions
• Should make separate hysteresis measurement scripts obsolete, this can be handled by the setpoints definition now. Test and remove
• Make accessible with device object measurments
• Test with real instruments
• Add documentation