Classifier is null safe.
API_Demo is null safe.
Precoinstructed Concepts is null safe.
Preconstructed LexicalPatterns is null safe.
ContentTypeNegotiator is null safe.
MediaType is null safe.
SearchedConcepts is null safe.
Preconstructed Patients is null safe.
SemanticModifiers is null safe.
DummySearchResult is null safe.
Use checker framework 1.7.2.
Zylab patis client is completely null safe.

- fixed checker parse errors caused by generic parameters not specified as non-null.
- Remove unneeded up–down cast.