Makes it possible to enable/disable table header with a boolean property (default to enabled).
Import / export mockups JSON, fixes #11
Removes old function call.
This function was removed in commit 468192b2620190aa868ace198d0fb7cb28bfb8dd, but not all refs to it were removed.
Merge branch 'feature/ticket11_import_export_mockups_json' into develop
Merge branch 'feature/fix_object_has_no_method_toggle_navigation' into develop