fix header hlist li selectors
[scss] some css gradients
[scss] use borders instead of background images
[scss] button gradients and mixins
[scss] rm bootstrap buttons
[scss] themable follow button
[scss] themable register button
[scss] themable close button
[scss] themable sidebar_nav
[scss] themable facets arrow
[scss] themable feedback button
[scss] rm unused images
[scss] feedback shadow
[scss] refactor misc
[scss] refactor forms
[scss] refactor type
[scss] refactor morelink
[scss] refactor tooltip
[scss] refactor button
refactor showhide_button