[TASK] Add constants.txt for default image
[TASK] Start support for default image
[TASK] Add default image
[BUGFIX] Insert default 'NULL' for og:type

Resolves Issue #6
[RELEASE] Release of version 1.2.2
[BUGFIX] Insert default 'NULL' for og:type

Resolves Issue #6
[RELEASE] Release of version 1.2.2
[TASK] Add constants.txt for default image

Resolves issue #2
[TASK] CGL
[TASK] Extend constants.txt for all attributes
[TASK] Remove documentation since reST rendering is not supported yet
[TASK] Remove watermark from constants
[TASK] Finish constants.txt fallback behavior
[TASK] Merge Documentation
[TASK] Merge documentation
[TASK] Set state to stable
[RELEASE] Release of version 1.3.0
[TASK] Merge development to master
[TASK] Fix conflicts
[TASK] Adjust TYPO3 dependency to avoid getting marked as outdated