moved spectrogram to arfview/spectrogram.py
added plotScrollArea which enables arrow key control of view range and zoom
fixed labelPlot to only display fixed number of labels
labelRegion no longer changes when the x range changes because all the label regions are cleared
increased label font size
changed downsamplePlot from using axis range to view box range
user can select labels by double clicking
can delete entries
can now delete labels with toolbar button
tweaks to selection color and zooming
change order of key presses in space bar labeling
removing relative imports
removed another relative import
changed default xrange for long recordings
fixing temporary arf label files
no spectrogram for undefined data