Added MicrodataItem.getId IT for trimming URL
Tightened MicrodataItemTck IT
Repurposed MicrodataItem.hasLink into getLinks
Added ITs for MicrodataItem.getItems multiplicity
Pulled up link methods from document/item into HypermediaContainer
Pulled up getLink implementation into AbstractHypermediaContainer
Pulled up MicrodataDocument.getForm into HypermediaContainer