Merge pull request #20 from nsendetzky/master

Creates separate address, list and list type manager like in the core
Merge pull request #21 from nsendetzky/master

Adds PHP 5.5 for travis builds
Merge pull request #22 from nsendetzky/master

Adds SQL statement for aggregating list items
Merge pull request #23 from nsendetzky/master

Extends aggregate SQL statements to allow sortations and correct slicing and adds test
Merge pull request #24 from nsendetzky/master

Clears the manager/controller factory caches to avoid side effects
Adds travis-ci status