Removed obvious method return types
Removed ByteUtils trait from TswRdb
Added jackson dependencies to API
Removed redundant import
Updated sbt-idea plugin
Refactored string reading

Moved RdbString to a more suitable place
Changed signature of RdbStringFileReader.getStrings to return a header,
Vector[RdbString] tuple. This is for client code to be able to discern
what category the Strings belong to. This also simplifies XML
transformation code
Renamed the StringXml transformation class to something more inline with
other class names
Merge branch 'develop' into feature/output-json
Added a JSON RdbStringDataTransformer
Moved all language table reading from client to client code in
RdbStringDataExporter

This is so clients of RdbStringDataExporter do not have to worry about
reading the language table
Made default output XML and added a flag --json to output JSON
Updated README with new usage example with JSON string export. In addition
to the new usage
Merge branch 'feature/output-json' into develop