Add hw schedule for UHFLI, as well as allow the use of natively inverted VG matrices.

Created by: NicoHendrickx

Two commits. The first adds a hw schedule which can be used with (a slightly modified version of the driver of the) Zurich Instruments UHFLI lockin. The second commit allows the use of a VG matrix that is natively inverted. This saves a bunch of matrix inversions, as well as allows for the input of non-square matrices. The default is still backwards compatible of course.