added address, hasNestedData and default values to item table
added documentation; callbacks; address error bugfix (when not defined)
added overlay template
removed empty line
removed outcommented code
Merge pull request #18 from sulu-cmf/feature/item-table-improvements

[FEATURE] added address, hasNestedData and default values to item table
removed rowcount decrease (since that leads to bugs)
adaption in item-table
removed unnecessary code
cleanups
Merge pull request #19 from sulu-cmf/feature/item-table-improvements

[FEATURE] item table improvements
added build files
merged with develop