Add a type_name field to RampMeterLsdValue and RampMeterRamValue to make it easier to understand their types (numeric id wasn't enough).  Joint checkin with one on model-database-access repo.
Changes to be committed:
modified:   src/main/java/edu/berkeley/path/model_objects/scenario/RampMeterLsdValue.java
modified:   src/main/java/edu/berkeley/path/model_objects/scenario/RampMeterRamValue.java
modified:   src/main/resources/scenario.xsd
Fix the getters for the start_time to create a DateTime of the right type rather than attempt a cast that doesn't work.
Changes to be committed:
modified:   src/main/java/edu/berkeley/path/model_objects/scenario/RampMeterScheduleElement.java
modified:   src/main/java/edu/berkeley/path/model_objects/scenario/SignalPlanScheduleElement.java
Merge pull request #174 from tmkpath/dev

Two fixes to support ramp-metering