Debug will return a debug(format, arg, arg...) function for which messages will be printed if the DEBUG environment variable is set.

Download downloads the request file in the url.

Markdown strips space indentation and replaces ' with `, allowing for markdown to be written as indended multi-line strings.

Parallel takes a list of functions and calls them all in concurrently, returning when all the functions are done.

Spawn N go routines and wait for them to return.

SpawnWithLimit N go routines running at-most limit in parallel and wait for them to return.

StringList is a list of strings and useful methods.