add parsing for groupby functionality
initial changes for groupby feature in Resolver
changes to support grapher/resolver groupby function
comment out debug statements
fix to ensure grapher picks up datasource
changes to further resolve datasource bug and pipeline output file bug for groupby placeholders
update
add in ability for groupby step to have append and prepend commands
changes to ensure dependencies are correct on steps that are groupby and refer to other groupby steps
fix so that groupby works on datasource fields
update packed file
Allow symlink to take a datasource option
Make jobs dependent on a previous once step
updates on groupby and symlinking
add to .gitignore and cleanup