Updated header logo

Updated the header logo to be in colour, also created a 'image_files'
folder for keeping image masters.
Updated system logo

Updated system logo with Taarifa logo and branding.
Updated login logo

Updated the login logo with a colour version.
CSS to accomodate larger logo

Have changed the CSS to accomodate a larger logo on installation. Have
also commented out the background file to stop 100kb from being
downloaded to compensate for the larger file size.