update mysociety tab

update to new logo
remove donate and our site links
move footer menu css into base scss files

also hide footer menu on mobile
add privacy link to main menu, hide on desktop
hide footer nav on alerts index page

easier than dealing with the problem of the photo aside obscuring the
nav
Internet Explorer tweaks for front page resdesign

Make mySociety tab wider to fit logo
Just display text for FixMyStreet Platform link
remove border on front page .content to stop odd line under footer