server: LiberviaRootResource now manages root url redirection, and former redirection has been replaced by it: as a nice side effect, the root URL doesn't show "libervia.html" anymore (LiberviaRootResource actually do URL rewritting).

try:
    from common.constants import Const as C
except ImportError:
    pass # import doesn't work at this stage with pyjamas
else:
    __version__ = C.APP_VERSION