adding a test for most specific editor added by a sub-language
Merge remote-tracking branch 'origin/master' into 3.0/multipleEditors

Conflicts:
	languages/languageDesign/jetbrains.mps.lang.editor.multiple.testLanguage/languageModels/editor.mps
	languages/languageDesign/jetbrains.mps.lang.editor.multiple.testLanguage/languageModels/structure.mps
Merge remote-tracking branch 'origin/master' into 3.0/multipleEditors