[items] Allow Item lookup by name directly on the `items` namespace

[digitaldan]

Fixes #232

Signed-off-by: Dan Cunningham dan@digitaldan.com

[digitaldan]

Hmm, i need to update the docs as well, i do that shortly

[digitaldan]

Ok, was not sure the best way to document in JSDoc, this was the best i could come up with.

[digitaldan]

Thanks!