Sets correct speed limit if speed set by signal exceeds overall speed limit (bug 1157182].
Correction of multi_dist_sig_mr processing which returned incorrect state if only one signal was found, furthermore it will also return state in no 'end' signal is found.
Correction in route processing for looped routes without signals.
git-svn-id: http://svn.uktrainsim.com/svn/openrails/trunk@1506 a9f3cfff-6c41-7446-b0ca-052bd761e6eb