Added explicit check on javax.inject.Named annotation

Hi Tatu,

Hereby I'd like to offer a pull request for the GuiceAnnotationIntrospector in your jackson-module-guice project. In the original code, I noticed that only Guice injection worked for me. I have created a unit test on the extension I wrote for the GuiceAnnotationInspector, which you can find at: https://github.com/cvuijst/jackson-guice-unit-test-for-javax-injection. As the unit test shows, your code now supports both Guice injection and javax injection.

As this is my first Git experience, I hope this follows procedures,

Best regards,

Charles Vuijst