Add instructions to cd into directory with package.josn
Add instructions to cd into directory with package.josn

Fixes #564
uwdata/vega-lite,freeman-lab/vega-lite,smartpcr/vega-lite,smartpcr/vega-lite,ellisonbg/vega-lite,mathisonian/vega-lite,uwdata/vega-lite,vega/vega-lite,uwdata/vega-lite,ellisonbg/vega-lite,vega/vega-lite,freeman-lab/vega-lite,vega/vega-lite,freeman-lab/vega-lite,uwdata/vega-lite,smartpcr/vega-lite,ellisonbg/vega-lite,vega/vega-lite,mathisonian/vega-lite,vega/vega-lite,uwdata/vega-lite,mathisonian/vega-lite