Added method to IntersectionPlanSet to get a SignalPlanSet by its ID, and
modified the test to call it.

Changes to be committed:
modified:   src/main/java/edu/berkeley/path/model_objects/scenario/IntersectionPlanSet.java
modified:   src/test/java/edu/berkeley/path/model_objects/scenario/IntersectionPlanSetTest.java
Remove IntersectionPlanSet and RampMeterPlanSet from XSD and remove derived objects.
Attach SignalPlanSet and RampMeterPlan objects to their controller.

Changes to be committed:
modified:   src/main/java/edu/berkeley/path/model_objects/ModelObjectsFactory.java
modified:   src/main/java/edu/berkeley/path/model_objects/scenario/Controller.java
deleted:    src/main/java/edu/berkeley/path/model_objects/scenario/IntersectionPlanSet.java
modified:   src/main/java/edu/berkeley/path/model_objects/scenario/RampMeterPlan.java
deleted:    src/main/java/edu/berkeley/path/model_objects/scenario/RampMeterPlanSet.java
modified:   src/main/java/edu/berkeley/path/model_objects/scenario/Scenario.java
modified:   src/main/java/edu/berkeley/path/model_objects/scenario/SignalPlanSet.java
modified:   src/main/resources/scenario.xsd
deleted:    src/test/java/edu/berkeley/path/model_objects/scenario/IntersectionPlanSetTest.java
modified:   src/test/java/edu/berkeley/path/model_objects/scenario/RampMeterTest.java
Merge branch 'dev' of https://github.com/calpath/model-objects into dev
Merge pull request #171 from tmkpath/dev

Remove IntersectionPlanSet and RampMeterPlanSet from XSD and model-object