ported IsabelleHyperlinkDetector to Scala and updated to Isabelle 2013
contribute IsabelleHyperlinkDetector via SourceViewerConfiguration, not via extension point (allows reuse in non-editor based viewers, e.g. ProverOutputPage)
moved hyperlink target to editor configuration
HyperlinkUtil no longer needed (part of IsabelleHyperlinkDetector now)
ported Isabelle command hyperlink to Scala
ported TextHyperlink to Scala
Merge branch 'hyperlink' into isabelle2013
cleanup unused
indicate that Isabelle 2013 is required