r864: Merge 2.1:

r864: Merge 2.1:
Many, many changes in the plugins:
* Converted some plugins to implement process_buffer() instead of
  process_realtime().
* Rename the plugin 1080to480 to 1080to540.
* Brighness/Contrast: Put a label on the sliders.
* Chroma key (HSV): Fix rounding.
* Provide a label on the sliders.
* Extend the slider range from 100 to 1000.
* Remove the "Adaptive" option from the deinterlace plugin.
* Diffkey: Use a macro to declare variables (will be reused for
* OpenGL).
* Don't convert to yuv to rgb.
* Dissolve: Make the fade fraction a member (will be needed for
* OpenGL).
* Remove line doubling options in Frames to Fields and Freezeframe.
* Gradient improvements.
* Rework Histogram plugin.
* Hue/Saturation: remove unused files.
* Hue/Saturation: Provide labels on the sliders.
* Inverse Telecine: Improvements and automatic deinterlacing.
* Linear Blur: Optimization and allow a larger blur length.
* Removed the Linearize plugin.
* Motion tracker: Make it more general.
* Motion Blur: Change the picture, use half the user-specified radius
  (doesn't this change the behavior?)
* Overlay plugin: Declare it as synthesis plugin; support the
* Maximum menthod.
* Parametric plugin: Fix the line drawing.
* Reverb plugin: Use the macro for the window close event.
* RGB<->601: Reduce rounding; improve checkbox labels.
* Rotate plugin: remove unused files.
* Rotate plugin: Use accessor functions to get to the frames.
* Scale: Apply a small increment to the tumblers.
* S.U.V.: remove unused images.
* S.U.V.: Make the title and plugin stripes dimmer.
* S.U.V.: Resize the plugin dialog.
* Timefront: needs the color tools.
* Rewrite the Interpolate plugin.

Assorted minor changes:
* Warn on startup if shared memory is too small.
* Update plugin GUIs more often.
* Reduce rounding errors when edits and labels are located.
* Add Input, output, and temporary frame accessors to PluginVClient.
* Prepare the Affine engine for rotation by OpenGL.
* Whitespace and indentation.
* Small optimization in plugincolors.C.