Added profiling command line flag
ModularProgram now correctly triggers ModularVisual.update
give SceneCanvas symbolic Entities to represent ndc, fb, and lpx coordinate systems
Merge branch 'transforms-subpackage' into transform-cache

Conflicts:
	vispy/scene/transforms.py
Implemented basic transform caching; testing needed.
Corrections to SceneEvent transforms
Fixed transform issues; more testing needed
Fixed transform cache handling
Optimization
Fixed bugs
Merge branch 'master' into transform-cache

Conflicts:
	vispy/scene/transforms/__init__.py
Added grid_large example and grid startup optimizations
Added transform caching to mouse events
Optimizations for grid_large
Add Texture.__repr__
minor edits
Added note about SceneCanvas use of TransformCache
New n-dimensional scatter plot example with GPU-based smooth projections.
Added datasets package with load_iris() function.
Minor simplication in OrthogonalPath.