Query: more work on collections
Toy language defined in newLanguageDesign
Empty set/list constructs
More sample query code in mps.sample.queryTest
Fixed a typesystem rule in core.query
Removed empty lists (they are no longer valid) from a sandbox model
Fixed one getType() method in core.query
Moved newLangDesign sample language to proper place
Regenerated
GeneratorsRunner
Merge branch '3.1/danya'

Conflicts:
	plugins/newLanguageDesign/languages/query/source_gen.caches/jetbrains/mps/core/query/editor/generated
	plugins/newLanguageDesign/languages/query/source_gen/jetbrains/mps/core/query/editor/trace.info