Add icon selector to save icons as png

Created a icon selector allowing people to modify the colour/size of the icons and save as a png file.

Will make it easier for people who aren't familiar with web design/css to use the icons.

Live code running here: http://pyko.github.io/webfont-medical-icons/icon-selector.html
Some minor changes to the index too: http://pyko.github.io/webfont-medical-icons/