Add larger click target to buttons

The outer edges of buttons activate the element's active state but do no
register clicks. This creates a pseudo-element which is larger than the
button and occupies the gap it creates when it moves (when in active
state).
Add border-top hack for input buttons

Inputs cannot hold child elements so pseudo-classes will not help
increase the click target. Inputs do not seem to have the problem with
the space below their text being unclickable.

The remaining problem is that the button moves away from the cursor when
clicked at the top. This adds a border-top to catch this.
Tweaks for the input button fix
Make border-top fix only apply to inputs
Adding new images for buttons

button-base-edge.png for a fake bottom border for submits in IE6 & 7
icon-pointer-indexed.png for a version of the button arrow that works for IE6
Convert image to png8
Add new styling to IE<9 buttons + fixes for others

IE<9 buttons to now have a border-bottom like the box-shadow of others.
Merge branch 'master' of github.com:alphagov/static into fix_button_click
Merge branch 'fix_button_click' of github.com:alphagov/static into fix_button_click

Conflicts:
	app/assets/stylesheets/_buttons.scss

Also includes some cleaning up
Add missing states for IE6 & 7 and fix issues

IE6 & 7 do not recognise :focus or :active & :hover only on links:

http://www.quirksmode.org/css/contents.html

This is a JS shim for that as well as fixes for all the issues caused by
this implementation & some cleaning out of dis-used CSS.
Merge branch 'master' of github.com:alphagov/static into fix_button_click
Rebuild list of categories in the footer to be more accessible and match the list order and layout of the categories on the homepage
Merge pull request #124 from alphagov/fix_button_click

All good
Update external-links to recommended-links

This is necessary because of a change in Frontend:
https://github.com/alphagov/frontend/commit/5f0fa0143dce47f5aa871ba19efa532a83665cde
Add Inside Government links to the global footer
Change input submits to buttons

To allow CSS changes to work from:

alphagov/static#124
Merge branch 'master' of github.com:alphagov/static into inputs_submits_to_buttons
Replace input for button on 404
Correct placement of guides print CSS
Merge branch 'master' of github.com:alphagov/static into guides-print-fix