Initialize default model store in init method

[goneall]

Fixes #284

NOTE: This requires a core library update which includes this PR: spdx/spdx-java-core#23

[goneall]

@dwalluck - please review - note it depends on an update to the core library to compile.

[goneall]

Note that we can not make use of the SpdxModelFactory.init(IModelStore modelStore, String defaultDocumentUri ...) in the unit test cases since the teardown uses the DefaultModelStore.initialize(IModelStore modelStore, String defaultDocumentUri ...) directly.

I'm now wondering if we should remove the SpdxModelFactory.init(IModelStore modelStore, String defaultDocumentUri ...) method and just initialize the DefaultModelStore if it has not already been initialized.

You can always call the DefaultModelStore.initialize(IModelStore modelStore, String defaultDocumentUri ...) before or after the init() call to control the defaults.

[pmonks]

@goneall that would need careful documentation and perhaps also a thrown exception in the event that someone tries to configure a non-default model store after init has been called (assuming model stores can't be switched at any time ofc).

[goneall]

@goneall that would need careful documentation and perhaps also a thrown exception in the event that someone tries to configure a non-default model store after init has been called (assuming model stores can't be switched at any time ofc).

Good point - I'm just going to remove the call to explicitly set the defaults on init. I'll also add some documentation.

[goneall]

I removed the call to explicitly set defaults on init and added documentation.

[dwalluck]

I've run my units tests both with and without initializing the DefaultModelStore and they pass.