[UI] Activates Saros/I toolwindow and component

And adds an icon for the tool window.

Change-Id: I08699fba83f356003e6c65fa93111388c8df0336
Reviewed-on: http://saros-build.imp.fu-berlin.de/gerrit/2015
Tested-by: Jenkins CI
Reviewed-by: Holger Schmeisky <google@schmeisky.com>