Added some new exception classes and fleshed out the documentation.
Refactoring the caching scheme
Parameterizing a function to specify the current Application Definition Graph.
Changed signature and documentation to readAppendixes() so that the appdef file comes first, and getAppDefFn is now called getAppDefGraphFn to distinguish better between the appDef file and the named graph that holds the file and its appendixes.
Clarified documentation of loadFileUri()
Clarified naming for parameter appDefGraphFn
getApplicationParameters needs to distinguish between the appDef graph and the appDef file.
Mainly changes to the way tracing is done