fa/box.cc: do not skip initialization of Box::selfReference_ field
fa/folding.hh: type 1 box unfolding heuristics + various fixes

  - let Folding::componentCut fail when cut signatures mismatch
  - invalidate signature cache after (un)folding
  - fix condition allowing to fold type 2 boxes at internal TA states
fa/forestautext.hh: improve FAE::makeDiskoint()
fa/normalization.hh: independent macro for type 3 candidate folding
add TA::getAcceptingTransitionCount() method
fa/fixpoint.cc: allow conditional normalization before learning type 3 boxes
fa/config.hh: new compile time options