the user-arrow now behaves the same way the rest of the header does.
tidied up the js with some nudges and combining the lines.
fixed the transition speeds of the header and the user arrow so that they match.
changed the background color to brightness.
changed the js for the header to animate rgba instead of a background color.
changed the js so it now applys a class instead of changes the background color.
cleaned up the js and the css so the css class is for css arrow and top-bar.
No need for rgba anymore
Merge pull request #61 from Precise-Pixels/user-nav-arrow

User arrow behaviour (it's been bad.)