"Share" icon displayed in detail page in phone version

The "share" icon gets displayed when the user accesses a details page,
it allows to share the item.

The "share" icon is displayed in the topbar at the same position as
the "refresh" icon.

In a proper implementation, the "share" icon would only be displayed
if there is a "share" add-on. Clicking on that icon would start the
"share" activity. Right now, add-ons are not checked and the hook is
not triggered. The action needs to be hardcoded in the "share"
function of "sleek.phone.js".

Notes:
- the icon is a copy of the "refresh" icon for the time being,
pending a better icon.
- the case when a datasource contains only one item is not supported,
meaning the "refresh" icon will be displayed in that case, not the
"share" icon.
- the case when the item cannot be shared (static local content) is
not supported either, meaning the "share" icon is always displayed.
CSS built (previous commit changed CSS)
Merge branch 'hack-share' into luakabop-buttons

Conflicts:
	app/index.phone.html