PIDE: more interactions in frontend interface:

CalcTree, getActiveFormula, moveActiveCalcHead, moveActiveDown,
moveActiveFormula, ...
... all concerning iteratorOK2xml.

We leave the old code until libisabelle is integrated.

 src/Pure

 src/FOL

 src/HOL

 src/ZF

 src/CCL

 src/CTT

 src/Cube

 src/FOLP

 src/LCF

 src/Sequents

 src/Doc

 src/Tools

 src/Tools/isac

 test/Tools/isac/ADDTESTS/session-get_theory/