the maximum upload size is now part of the response of the upload and de...

...lete operation.

the maximum upload size is updated within the browser once an upload or delete operation has been finished

this will fix #784 - one day ;-)

This is not yet perfect - especially the undo on delete causes still issues.
In addition we should subtract the size of the upload file from the max size before upload.

but feel free to test this and comment on the concapt

THX