Changed "undefined" to "undef" as the former clashes with Isabelle's own undefined keyword.
Added PO loop functionality; in theory we can detect that the Isabelle command associated with a given PO has successfully finished and update the PO status. Unfortunately this status does not appear to being updated in PO list viewer as such.
Merge remote-tracking branch 'origin/sdf' into ldc/tipi

Conflicts:
	ide/plugins/theoremprover/src/main/java/eu/compassresearch/ide/theoremprover/TPPluginDoStuff.java
PO and THY are now talking and the PO list is updating from Isabelle output
Added an icon for the proof "submitted" status in the PoViewer.
Failed POs are now removed from the Isabelle buffer so that additional lemmas can be proved afterwards
Implemented stack based representation of POs that have been submitted. Also added "enqueueAllPOs" which can be used to submit all POs for processing.
Fixed calls to classic and dev PTPs.
Intermediate changes, trying to debug TP-Plugin with Luis
Put back TPConstants reference, it seems to be working much better now :)
Merge remote-tracking branch 'origin/rjp' into sdf