Work in progress on getting markers to work
Fixed a problem where a sequence number could become negative
Vertical lines indicating spikes are now scaled appropriately for each data chunk
When drawing data, channels to draw are picked from the vislbleChanenls.
This is work in progress on issue #9
Changed the drawing code such that, instead of adding the channel offset to the vertices, each channel is translated on the fly to the correct offset
Selecting individual channels kind of works, but things get a bit strange when navigating between data chunks. Also, selecting channels within the selected channels does not work
Fixed an error where the y-span was not set properly when navigating data chunks while showing only selected channels
Fixed a problem where selecting channels among an already selected
subset of channels did not properly refer to that subset. This commit
addresses issue #9