Version updated to 2.1.3

Signed-off-by: Rafał Malinowski <rafal.malinowski@corp.bluecherry.net>
Changelog updated

Signed-off-by: Rafał Malinowski <rafal.malinowski@corp.bluecherry.net>
Merge pull request #144 from vogel/release-2.1.3

Release 2.1.3