parameter tmarks feature request

[aakash10gupta]

In some cases the seismograms shown in a record section will need to be marked with vertical lines at multiple timestamps. One special case is where each seismogram will have its own distinct set of marks. These sets can be provided as a list of lists.

An instance of where such a need arises is when the seismograms plotted in a record section correspond to different background models, and hence the expected arrival times of pulses can differ across seismograms. To plot vertical lines corresponding to the different sets of expected arrival times, the above requested feature would be needed.