[IMP] add icons for stat buttons
[IMP] add class for icon pencil
[MERGE] merge with latest trunk
[IMP] add icon for action
[IMP] add required icon
[IMP] small css tweaks to stat buttons (addon web)
[IMP] simplify the stat button html structure (one less span) (addon web)
[IMP] improves the css for the stat buttons: moves the css independent of oe_button_box to a oe_stat_button section to allow a better look when used out of the button box (addon web)
[IMP] small css tweaks to stat buttons (addon web)
[MERGE] merge from rma branch
[IMP] removes 2px to the stat button height, to save on vertical space (addon web)
[MERGE] merge from trunk
[MERGE] merge the last changes to improve the 'stat buttons' support in web

Many small tweaks/css changes to correctly display the stat buttons in
various situations (with/without icons, with/without strings, with sub 
widgets, ...)