gr-qtgui: adding function and slot to set a time display curve's color.
gr-qtgui: clean up
gr-qtgui: provide function and slot for setting the labels of a time curve.
gr-qtgui: multiple connections working, each with their own color.
gr-qtgui: Passing vectors of data to update plot for stability; also moving responsibility of keeping track of plot updates out to qtgui_sink instead of inside plot qidget.
gr-qtgui: moving towards allowing time plot to have multiple connections.
gr-qtgui: no need to check the version here since we require >4.4
gr-qtgui: adding copyright dates to qtgui files.
gr-qtgui: adding double-click point selector to main gui widgets.
gr-qtgui: cleaning up unnecessary plotting calls.
gr-qtgui: restructuring qtgui directory to new layout.