h1-code-refactor

This code has been refactored to improve accessibility. The HTML has been tweaked: initially lots of div elements were present: many of these have been replaced with semantic html elements. The structure of html elements should now follow a logical structure. Alt attributes have been added to all images. A title element has been added. Comments have been added to the html and css in order to make navigating easier for the novice. Both the html and css have been tidied. Various classes and ids were removed from index.html. This has meant that the same result has been achieved with fewer selectors in css.