Added specific links to Linux, Mac, Windows in drop-down nav.
Only unique links are tested, test_links.py is MUCH more efficient.
Reports number of links checked, and number of unique links.
Merge branch 'master' of https://github.com/ehmatthes/intro_programming into visualization_earthquakes
Working general syntax example for kwargs.
Merge branch 'master' of https://github.com/ehmatthes/intro_programming into visualization_earthquakes