added gui and implementing the default search engine

test with: (or 'brave' 'forfeit') or (and 'brave' 'forfeit') in the gui
modify everything for supporting timeddocuments

* Occurence describes now a UUID for document + int for the timeslot
* TimedDocument are gathered into the DocumentRepository for later
retrieval
* TimedDocumentIndexer for indexing a bunch of timedocuments
* clean up of main methods
* Start LanguageSpecific class for doing things like tokenizing or
stemming
* Testing Java VLC binding without success