Deleting skipped stops does not work

[mattwigway]

When you delete a stop from a trip pattern that is skipped in a trip, the editor throws an exception:

java.lang.NullPointerException: Try to read stopId on null object models.transit.StopTime (models.transit.TripPattern.reconcilePatternStops, line 210)
    at play.classloading.enhancers.PropertiesEnhancer$FieldAccessor.invokeReadProperty(PropertiesEnhancer.java:213)
    at models.transit.TripPattern.reconcilePatternStops(TripPattern.java:210)
    at controllers.api.TripPatternController.updateTripPattern(TripPatternController.java:150)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at play.mvc.ActionInvoker.invokeWithContinuation(ActionInvoker.java:557)
    at play.mvc.ActionInvoker.invoke(ActionInvoker.java:508)
    at play.mvc.ActionInvoker.invokeControllerMethod(ActionInvoker.java:484)
    at play.mvc.ActionInvoker.invokeControllerMethod(ActionInvoker.java:479)
    at play.mvc.ActionInvoker.invoke(ActionInvoker.java:161)
    at play.server.PlayHandler$NettyInvocation.execute(PlayHandler.java:252)
    at play.Invoker$Invocation.run(Invoker.java:278)
    at play.server.PlayHandler$NettyInvocation.run(PlayHandler.java:230)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
    at java.util.concurrent.FutureTask.run(FutureTask.java:262)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:178)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:292)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:745)

[mattwigway]

Fixed in 959f3af but should have an automated test.