js2-mode is no longer developed and we recommend js-mode these days,
so switch the modelines to specify that, and make them consistent
across all files.
https://bugzilla.gnome.org/show_bug.cgi?id=660358
We had problems because the More links were reacting on press but
other elements were reacting on release. (Often the link would trigger
*and* an item.) Just connecting to ::button-release-event on
ClutterText gives a stuck grab (since ClutterText gets the press
but not the release), so we need more complicated code that we
encapsulate into a new class.
link.js: new "pseudo-widget" that implements a clickable link.
overlay.js: Use Link.Link for the More.. links
http://bugzilla.gnome.org/show_bug.cgi?id=573323
