doc: tweak markdown quoting
doc: tweak Markdown header syntax
doc: tweak Markdown to use `<kbd>` tag
doc: italics instead of boldface
doc standardize quoting + install instructions
Ability to customize default suggested URL length

From @cmcmahan of Muppet Labs.  Closes #4.
doc: TOC, list formatting
bump version
travis-lint no longer permits language emacs-lisp