Changes modals to use font awesome for modal close link instead of "close" text
Changes modal to automatically be centered within overlay div (modal stays in center of the page when window is resized).
Changes modal overlay opacity to RGBa, changes structure of modal HTML (everything now within the overlay div).
Adds body background color to background of modal
Changes overlay color for modal to be darker, removes comments from CSS
Change ruby version back to 2.0.0
Merge pull request #37 from sea-lions-2014/mh-modal-changes

Changes modals to use font awesome for modal close link instead of text