[ticket/12598] Improve search box styling

PHPBB3-12598
[ticket/12598] Add lt IE9 fixes

In case this one gets merged before hanakin's gradient PR.

PHPBB3-12598
[ticket/12598] Remove unused link colors

PHPBB3-12598
[ticket/12598] Clean up unused link colors

PHPBB3-12598
[ticket/12598] Add some responsive margin to give breathing room

PHPBB3-12598
[ticket/12598] Remove hover border-color and use hover icon

PHPBB3-12598
[ticket/12598] Add IE hax documentation

PHPBB3-12598
[ticket/12598] Add IE8 hax to avatar (to exclude IE9)

PHPBB3-12598
[ticket/13009] Remove IE 7 hacks

PHPBB3-13009
[ticket/13009] Cleanup the remaning css

PHPBB3-13009
[ticket/13009] Minor comment changes

PHPBB3-13009
[ticket/13009] Remove extra space

PHPBB3-13009