Fix arguments for hfs-textline
Use output-mapping to determine sink or source (idea in progress)
simplify fnk macros
better name for sink step
Only forward arguments that are in the input-schema
use get-out-fields accessor instead of keyword lookup
Remove tmp directories before starting step
Add transact function, a function that can wrap a nodes before and after a graph. 

Useful for cleanup steps like remove a Pail snapshot