gr-qtgui: time domain sink now shows and receives updates.
gr-qtgui: adding .i file for time domain plot and updating Makefiles.
gr-qtgui: adding double-click point selector to main gui widgets.
gr-qtgui: adding new qtgui_util.h to handle plot picker machinery.
gr-qtgui: removed OpenGL calls; we still link against the QTOPENGL_LIBS because of some dependencies in Qwt.
gr-qtgui: removing uncessary file of qtevents and objects.
gr-qtgui: wip: moving and renaming files for new structure.
gr-qtgui: restructuring qtgui directory to new layout.