deactivated preservation of <abbr> tags in the description fields
removed unused classes and database table
* AbbreviationsOccurrences not needed since we decided to remember the whole abbreviation list client side
* removed logic to save abbreviation occurences in Importer
* removed unused KeywordSearchServiceMock
Merge branch 'issue/35' into xmlimport

Conflicts:
	backend/src/main/java/de/fusionfactory/index_vivus/models/scalaimpl/DictionaryEntry.scala
Merge remote-tracking branch 'origin/issue/35' into issue/35