Fixes:
[cast] redundant cast
[rawtypes] found raw type
[serial] serializable class has no definition of serialVersionUID
Also suppress warning: auxiliary class TargetLanguageBase in ./inherit_target_language.java should not be accessed from outside its own source file
Affects marshalling of negative numbers from Java to C only.
A cast to signed long long in the C layer will now result in the expected value.
Closes#623.