Allow RECIPE and STYLE to be specified in bake-book
Allow RECIPE and STYLE to be specified in bake-book

If the user wants to specify their own recipe or style css files, they
can do it by setting the `RECIPE` and `STYLE` environment variables
respectively.

Connexions/cnx-rulesets,Connexions/cnx-recipes,Connexions/cnx-rulesets,Connexions/cnx-recipes,Connexions/cte,Connexions/cnx-rulesets,Connexions/cnx-rulesets,Connexions/cnx-recipes,Connexions/cnx-recipes,Connexions/cte,Connexions/cnx-recipes