Update state.changeHead to new syntax
Fire state events from StateChange

Otherwise calling a redo can never trigger events - which e.g. broke
down redo in the dependencyTree

Works on #323
Minor refactor in state.change()
Fix a typo in state
Fix StateChange specs
Remove tokens in batch mode

because they can lead to follow up changes.
Don't redraw the tree on tokenAdded

... led to an ugly screen flickering.
Fix undoing of tokenRemoved
Merge pull request #346 from latin-language-toolkit/undo_redo_fixes

Undo/redo fixes