Buffered 1D measurements with different number of setpoints do not work

[THuckemann]

As the buffer settings (and especially the number of setpoints) are only checked and altered at the beginning of a measurement,
it is currently not possible to have multiple measurements started with only one script (e.g. 1D Sweeps with multiple dynamic parameters)
with different setpoint length. The buffer settings are then only adjusted for the first dynamic parameter, for the following ones an Exception is raised when the measurement data is written into the QCoDeS database as the number of setpoints does not match.