[FR] Add ability to run a single recipe

[jby]

It would be nice to be able to click on a recipe in the list and choose "Run this now", and maybe (but no requirement for this single run request) always run MakeCatalogs even after a single recipe run.

[grahampugh]

Hi @jby, to run an individual recipe, click on the Run button inline with the recipe. Let me know if the wording in the README is not clear enough on this.

[jby]

I see, but that seems to only apply to recipes already in a list, see comment on #22 as well...