[v0.7 development] Fix advanced correction handling after major refactoring

[proycon]

Major refactoring (issue #41) broke some of the advanced correction handling. The most common functionality works already though. This is testable using the correctionexample.folia.xml document. The following sums up the current state:

• Corrections
  • non-structural: ok
  • structural (word)
    • merge: ok
    • split: ok
    • insertion: ok
    • deletion: fixed
    • nesting in current: ok
  • structural (sentence): partial: renders new sentence, but no access to original
• Suggestions for correction
  • non-structural: ok
  • structural
    • merge: ok
    • split: ok
    • insertion: fixed
    • deletion: ok
    • suggestion over a nested correction (correction/current/correction): fails [regression, works in v0.6]

These functions are needed if FLAT is to serve as a replacement for the Valkuil interface eventually.

[proycon]

Not all of these are regressions, some functionality wasn't ready in v0.6 either.

[proycon]

Most regression problems after refactoring are fixed now