unfinished refactoring of index typeclass
unfinished refactoring of index typeclass
Some changes to the new Index approach

- DmPrefixTree with v ~ DocIdMap
- add map function
  - fixed batchDelete with map instead of unionWith
making Occurrences a constant within InvertedIndex
small refactoring
started refactoring of indexer
Add keys function to Index and it's instances

 - ContextIndex
 - DmPrefixTree
 - ComprOccPrefixTree
 - InvertedIndex
   - performance may be increased by changing IKeys
     to String and skip packing all keys
Add TextIndex constraint type
Adjust Processor to the new (Text)Index structure

 - not all of the monadic functions are converted,
   only the exported ones (shallow)
Minor refactoring
Cleanup
TextIndexer refactored
refactored server with new indexer
refactored server with new indexer
moved some rarely used extensions from cabal file to the files were they are acutally needed
added simple interpreter to avoid compiler deadlock in current server impl.
added insert to interpreter with some basic tests
prepared test-suite
removed unused files
for some reason external modules crash ghc when data.aeson is imported within Docuemnt