Rename executable from gistwiz to gwiz
Symlink old executable name gistwiz to gwiz
Print warning but don't die when a gist has been changed on the local system; minor cleanup
add command: `gwiz reveal FILE` to sync down gists listed in FILE, and print HTML for a Reveal.js slideshow
Refactor duplication between 'down' and 'reveal' tasks
Use relative, not absolute paths to markdown in HTML output for Reveal.js
Update README: `gwiz reveal` command; Use from anywhere, writes to relative paths.