implements BoundInstanceInterface
fix documentation for scrutinizer
[#61] Fix for $isSingleton (by @craigjbass)

Fix for $isSingleton not containing correct value when using annotated
class koriym/Ray.Di#61
https://github.com/koriym/Ray.Di/commit/b77ab9f2accd7cb406109ec1831d966c
a268079c