Add hacked together vispy backend
Propagate resize event and fill in required graphics-context methods
Reorganize vispy components
Refactor vispy graphics context
Split up marker program
Rename ScatterArtist to MarkerArtist
Replace demo data with actual data plotting
Fix resizing of qgl canvas and vispy graphics context
Clear rendering-program stack after drawing
Add simple and dumb line drawing
Add graphics elements for drawing
Add support for variable line thickness
Rename colors for clarity
Add RectElement
Fix model transformation
Fix event handling on QGLBackend
Clip drawn elements
Persist and reuse drawing elements
Fix persistence of graphics state
Add text rendering based on vispy text visual