allows overriding fetcher repo recipes

[davemo]

• addresses #374 with a simple config override

• this allows users to override the fetch repository from their config/application.{js,coffee} like so:

  fetcher: {
   recipeRepo: "https://github.com/davemo/fetcher-recipes"
  }

[jasonkarns]

Can we kill the if else in cli main? It should still default properly if undefined