Code Cleanup & Recent upload on home page

### Changes (Theres a lot)
+ Header.php now includes the entire beginning of the document including head, navigation etc.
+ Footer.php now includes the entire ending of the document including the closing body, html tags as well as the main footer.
+ Anything with an ID has been replaced with a class (unless it is essential) - the reason for this is because classes can be reused anywhere whereas IDs cannot.
+ The greyBG div has been removed and instead the body has the grey colour. The reason for this is because content other than the header or footer have a white background (as well as other things) this means that most of the content is on a grey background anyway.
+ The H1 tags on the different sections have been replaced with a h2 tag because they are a similar size to what was wanted and so removing the h1 saves on css as well as makes more sense as they are not a main heading.
+ On the twitter section on the home page the link on "Team Verus" has been removed because the @ text already has a link to the same place.
+ The twitter feed container has been renamed from example1 to twitter-feed as it makes more sense.
+ the footer and header sections have been given a class of page-footer and page-header as this is more understandable.
+ main navigation has been renamed to page-navigation
+ added hover states to the big banner button and send button on contact form
+ two new classes transition and rounded. Transition adds a transition when something changes e.g. hover. and rounded adds a 5px border radius.
+ change the banner image so it stays put while the page scrolls. Adds a nice effect.
+ The small banner has been merged with the large banner except to give it an extra class of small.
+ Article elements have been replaced with divs as the article element refers to an actual article such as a blog.
+ Latest video now shows on home page