getSubmitters() can return null

[michelesalvador]

I tried version 1.9.0 and I encountered one problem.
With this version it's possible to parse a Json file only if it contains a subms key. Therefore Json files created with version 1.8.0 can no longer be opened because they don't have a subms key.
This is due to Gedcom.createIndexes() that calls Gedcom.getSubmitters() that can return a null subms object.
The same happens parsing a GEDCOM file: Gedcom.createIndexes() works only if the GEDCOM contains at least one SUBM tag.

[stoicflame]

Thanks for the report. Do you want to put together a pull request with the fix?

[michelesalvador]

Yes I will do that.