Added symmetrical parameter on cs_order

Pacemaker resource ordering by default is symmetrical. However, in some
cases ordering should only apply to starting of resources and not
stopping, for which symmetrical=false can be set on a resource.
Cs_order now does this automatically (default true), so it's also
backwards compatible.
Cherry-picking fix
Merge pull request #49 from kbon/Cs_order-symmetrical

Added symmetrical parameter on cs_order