add markdown files for example content
delete extname example, since it's in the paths example
add some utility functions, in particular `globFiles`, which returns an array of all file paths that match the given wildcard patterns, then reads each file and returns its contents as a string, and last, normalizes all line linefeeds in the string
reorganized some helpers
some interesting new file helpers that use globbing patterns. See "chapters" for an example of what they can do.