CoreBindingsEnhancement#appendGosuValue missing Boolean wrapper

[DPUkyle]

The type introspection in CoreBindingsEnhancement#appendGosuValue is missing a value for the Boolean type. This prevents structural type inference for JSON boolean "primitives".

[dougmccreary]

Just an aside on this: it seems weird to me that this code has to qualify all of the Java Boxed types. Seems like there should be a generic 'isJavaBoxedType' method somewhere that should be used instead.