Major overhauling - big collection of micro fixes and PHPDoc update.

Micro optimization in GeneralAjax and fixed indention in GeneralAjax.

Reworked PHPDoc in:
- GeneralCallbackDefault.php
- GeneralCollectionDefault.php
- GeneralDataDefault.php
- GeneralDataMultiLanguageDefault.php
- GeneralDataTableRowsAsRecords.php
- GeneralModelDefault.php
- InterfaceGeneralCallback.php
- InterfaceGeneralCollection.php
- InterfaceGeneralData.php
- InterfaceGeneralDataMultiLanguage.php
- InterfaceGeneralModel.php
Fix a warning when no filter has been selecten in the backend.
Use the automatic cbx class again
Merge branch 'master' into dev
Merge branch 'dev' of github.com:MetaModels/DC_General into dev
Merge branch 'dev' into contao3