The {@link org.teleal.lemma.anchor.CitationAnchor} class represents a single anchor in
an XHTML document, it's an adapter that ties into the org.teleal.common.xhtml.XHTML
document object model. The most common options of citation anchors are listed in the
{@link org.teleal.lemma.anchor.CitationAnchor.OptionKey} enumeration.
The {@link org.teleal.lemma.anchor.AnchorAddress} class encapsulates parsing and handling of
the href attribute value of a citation anchor. It is in fact similar to the
Java URI and URL classes, however, because these are rather dumb
abstractions, they can't handle URI's that do not use slashes to separate the authority from
the path. Hence, this had to be written from scratch.