Remove references to strings in the library project
Update projects to use Gradle
Add Polish translation
Add Russian translation
Make it easier to read external change log files

This change breaks getLog() apart to make it easy for subclasses to read
change log data from arbitrary locations.
By overriding getChangeLog() it's now also possible to use pre-merged
change logs. This method is also public, so users can get the change log
information and e.g. do the presentation on their own.
Link to Github contributors page for list of contributors
Update .gitignore