Added support for the Limburgish and Frisian languages
Moved some untranslatable stuff like settings to a different values file
Translated CopyIt-Android using Weblate (Limburgish)

Currently translated at 23.6% (17 of 72 strings)
Merge remote-tracking branch 'origin/develop' into develop
Added a checkstyle check to the Gradle build

The checkstyle check will only warn about errors but won't let the
build fail.
Improved the error handling and Javadoc in the application lock
Improved the Javadocs in the activatable class
Added more Javadocs to the string utility class
Added a unit test for the string utility class
Added Javadocs to the OSValidator class
Added a package-info file to the utils and copy_it packages
Added lots of Javadocs to the API service sync service
Added some Javadocs to the password generator class
Added Javadocs to the queue functionality
Added support for the Limburgish and Frisian languages
Moved some untranslatable stuff like settings to a different values file
Merge commit '694d777' into feature/gradle-build

Conflicts:
	android/res/values-li/strings.xml
Merge commit '5accd68' into feature/gradle-build
Merge commit '782dc9c' into feature/gradle-build
Improved the StringUtils unit tests and handling of strange arguments