Use vendor prefixes to reset box-sizing.

Firefox and older webkit doesn't understand "box-sizing: content-box", but do have vendor prefixes for it.

Bootstrap >= 3 sets the box-sizing to border-box using vendor prefixes and messes up the tabs layout, forcing us to use
them to reset it.  First reported in #32.
Defensive css
class for the pixelping img tag

Allows for users who embed a document to style around bugs with our the pixel interacts with their base template.
Better class name
Merge pull request #35 from palewire/patch-1

CSS class for the pixelping img tag
Make sure page images are the right height.
push search cancel button back into place.
Scope or remove unstopped class styles for pages.
Merge branch 'master' into translation
Updated translations