Updated Package Stack (markdown)
Added babel-root-slash-import and react-treeview to wiki page.
There was a typo in the package json for the test script. Darn.
Updated testing dependencies
Added Jest to package stack
Added missing sass-loader dev dependency
Needed to add webpack-dev-server since it was missing
Initial Package Stack wiki page. Declares why we are using certain prod, dev, and global packages. Also lists commands for each package category.