Made Insert and Update separate constructors in Interpreter

- add route for update
- minor cleanup
Cleanup and minor refactoring
Rename 'ContextIndex.member' to 'hasContext'
Cleanup
Fix: Insert fails properly if the document already exists

- add 'member' function to TextIndexer
- adjust tests
Replace unary Not with binary AndNot (former But)

- this way NOT can only be used with two terms
  -> remove 'allDocuments' function because it's only use is for a
     unary NOT without a preceding term
  -> previously pretty much required optimize is optional now
- adjust and add tests
Fix incomplete 'checkWith'
Restructure Schema, Normalizer and Analyzer