add support for named attribute injection

Hi Adam,

find attached a small contribution that adds support for named attribute injection.

It allows to inject directly default system properties which key use a dot naming (ex: user.home) and thus cannot be used as an attribute name in a Java class.

I found it usefull for example to write things like:

    @Inject
    @Named("line.separator")
    private String ls;

    @Inject
    @Named("user.dir")
    private String workingDir;

Regards

Matthieu Brouillard