Removes vendor directory because it's automatically created when needed
Merge https://github.com/Arcavias/arcavias-core
Tests for both, item and node children
Changes tree helper implementation to create only html tags if there are really children as hasChildren() can say yes if there is at least one in the database but was not fetched
Merge pull request #220 from nsendetzky/master

Removes vendor directory and tests for both, catalog item and tree node children