cleaned up examples

ViewBox: made padding more consistent for all auto-ranging methods, deprecated autoRange(item=) in favor of autoRange(items=)

 - disabled opengl (performance issues in Qt 4.7)
 - numerous caching changes (disabled deviceCoordinateCache due to performance issues)
 - speed up loading large images in ImageView
 - bugfixes from Ingo Breßler
 - Transform rotation bugfix
 - Added debug module
 - Major performance enhancements for scatterplot, fixed point clicking issues
     ** API change for scatterplot click signals
 - Drawing on ImageItem is working well now
 - PlotItem downsampling no longer uses scipy.signal.resample (this was creating artifacts)
 - Fixed ViewBox behavior when aspect-locked

 - numerous fixes in close() functions
 - added Transform class
 - ROI widgets now operate in degrees instead of radians for easier Qt compatibility

  - converted most old-style signals into new-style for PySide compatibility (beware: API changes)
  - removed ObjectWorkaround, now just using QGraphicsWidget
  - performance enhancements, particularly in ROI.getArrayRegion
  - numerous bugfixes

 - added vertical lines / regions for plots
 - added gradient editor widget
 - many bugfixes
 - cleaned up imageview a bit