Spelling corrections
Prevent Buffer being deleted when one of its Views is deleted.
Very simple line visual is written, demonstrating:
* shader compositing via reusable functions
* transform functions that can be bound to program variables
Added basic TransformChain
Cleaned up TransformChain a bit
Added Affine, Log transforms
Added color to line visual
Starting generalized shader compositing
bugfixes; basic compositing and binding are working.
compositing system gets basic function chain
bugfixes; line visual example is running again.
Removed warnings printed when GL functions are not found.
 - Missing functions may well be the normal state; all OpenGL stacks are not equal.
 - If we attempt to _use_ a missing function, a descriptive error is raised,
   so it is unlikely anyone will miss these messages.
Merge branch 'master' into visual_transform_chains
Previously, record arrays with only a single vield were interpreted as
having no fields at all. This has the awkward consequence that
vbo['field_name'] does not work when the dtype has only one field.
minor edits
fixed line visual example
added PolarTransform
Added parallel scenegraph architecture to be compared / merged with Almar's
filling in code.. grid almost works.
grids, multiple parenting are working
Added Qt message handler:
  - pushes all Qt messages through python logging
  - Ignore spam "QCocoaView handleTabletEvent ..." messages
Set background color in line_visual example