Start on data pipeline
Improve as.pipeline. Ignore NULLs
First pass at transform_bin implementation
Make split a pipeline component
Add installation instructions
Convert transform_smooth to pipeline model
Create check_prop function.
And beef up prop_type
Re-roxygenise
Trim pipelines to sources, and add c.pipeline()
Fix roxygen doc typo
Add pipeline tests
Preserve constants in transformations
Remove unnused function
Add as.pipeline.pipe
Remove ... from flow generic
Complete vega marks spec and add some docs
Better mark docs
Remove too-early branch function
Make data pipeline work in basic graphs
Strip whitespace