Datatype parsing support and access for portico

[michaelrfraser]

This PR adds datatype parsing and referencing support to portico.

• FOM datatypes are represented by the IDatatype interface. The method IDatatype.getDatatypeClass() returns the specific class of datatype. References to IDatatype can be casted down to their specific representation which is one of BasicType, SimpleType, EnumeratedType, ArrayType, FixedRecordType and VariantRecordType.
• FOM datatypes can now be queried through the ObjectModel
• Standard MIM datatypes are injected into the ObjectModel,
• All MIM attributes and parameters are created with their corresponding datatype
• Added datatype parsing to the 1516 and 1516e FOM parsers and model merger
• Added a new Rti1516eDtxAmbassador. This RtiAmbassador is a simple extension of the Rti1516eAmbassador, but contains extra methods to query the datatypes of attributes and parameters.

Extended Rti1516eDtxAmbassador methods to query datatypes are:

public IDatatype getAttributeDatatype( ObjectClassHandle whichClass, AttributeHandle theHandle )
        throws AttributeNotDefined,
               InvalidAttributeHandle,
               InvalidObjectClassHandle,
               FederateNotExecutionMember,
               NotConnected,
               RTIinternalError

public IDatatype getParameterDatatype( InteractionClassHandle whichClass, 
                                   ParameterHandle theHandle )
        throws InteractionParameterNotDefined,
               InvalidParameterHandle,
               InvalidInteractionClassHandle,
               FederateNotExecutionMember,
               NotConnected,
               RTIinternalError

Access to these methods is through an RtiAmbassador created by the "portico-dtx" RtiFactory. In code, creation and access would look as such:

RtiFactory factory = RtiFactoryFactory.getRtiFactory( "portico-dtx" );
Rti1516eDtxAmbassador dtxRtiAmb = (Rti1516eDtxAmbassador)factory.getRtiAmbassador();

//  ... Create/Join federation execution etc ...

IDatatype attributeType = dtxAmbassador.getAttributeDatatype( someOCHandle, someACHandle );
IDatatype parameterType = dtxAmbassador.getParameterDatatype( someICHandle, somePCHandle );

I have also added a suite of unit tests to test the parsing and linking of datatypes, and have tested the parser against all test reference FOMs (RPR, Restaurant, Standard MIM etc).

[timpokorny]

Dammit. Changed branch name to match local convention but that has closed the PR. Bringing it back.

[timpokorny]

Base PR completed with some minor changes:

• Removed Dtx ambassador and factory
• Added hla.rti1516e.extensions.RTIambassadorEx interface (more general)
• Added Rti1516eAmbassadorEx that extends RtiAmbassador
• Made Rti1516eAmbassador abstract and updated all factories to always return this type
• Fixed some small typos and false-positive on a test
• Updated some formatting things (DON'T YOU LOVE WORKING WITH ME!)

Main change was in the way that the extension is exposed. I have resurrected the old JLC naming convention of RTIambassadorEx and extended the default namespace (ohhhh!) so avoid having to case down to some special internal implementation. Will expose all custom extension methods here as an easy entry point. Made an impl side class with the extension methods and updated so that we only ever create instances of it. As such, we're only ever returning one implementation ever and it's entirely up to end-user to choose which view they want of it.

Also added a getFOM() method to the RTIambassadorEx so that users can access the ObjectModel directly to avoid any chicken-and-egg situations when trying to extract data types for an unknown object model.

Only open question is whether we should also expose the FOM parser as a standalone thing as well. Can leave that for a separate task.