clarify SourceNode use
clean up attachment calculation comment
fill in missing blur amount values
pipeline machinery to make and connects nodes
rename Pipeline to PipelineContext
migrate connections from the node to the context
rename PipelineContext to Context
update Pipeline references to Context
simplify how connections are stored
blow out some empty lines
Merge branch 'refs/heads/contextualized'
add fixed output port

The "image" output port was previously implied but why not add it?