adding HVI markers and master clock for sequence

docs/autodoc/segment.rst

docs/autodoc/segment_IQ.rst

docs/autodoc/segment_base.rst

docs/conf.py

pulse_lib/examples/psb_example.py

pulse_lib/segments/data_classes/data_HVI_variables.py

pulse_lib/segments/data_classes/data_generic.py

pulse_lib/segments/data_classes/data_pulse.py

pulse_lib/segments/segment_HVI_variables.py

pulse_lib/segments/segment_IQ.py

pulse_lib/segments/segment_base.py

pulse_lib/segments/segment_container.py

pulse_lib/segments/segment_markers.py

pulse_lib/segments/segment_pulse.py

pulse_lib/segments/utility/data_handling_functions.py

pulse_lib/sequencer.py