moved serial submit rule to DocumentModel
ported IsabelleCorePlugin to Scala and moved to .internal package;
using IsabelleCore object to access Isabelle from other plugins
no longer used (not updating IsabelleCorePlugin references)
Merge branch 'core-plugin' into isabelle2013
fixed Scala 2.10 warning about postfix operators
include Scala compiler into the feature, since it contains scala.reflect (needed for .launch)
using Scala 2.10 implicit class instead of implicit method
session options are not managed differently: hardcode the flush delay for now
updated to match changes in Isabelle2013 session API
updated to match changes in Isabelle2013 theory loading API
reformatted imports
more explicit Java->Scala conversion
Merge branch 'doc-model' into isabelle2013