Added first version of CircuitBreaker and ElectricPowerSupply classes
Note: With the default TCS script, TCS emergency braking now provokes a circuit breaker opening if EmergencyCutsPower is specified in the monitors.
git-svn-id: http://svn.uktrainsim.com/svn/openrails/trunk@2410 a9f3cfff-6c41-7446-b0ca-052bd761e6eb