Keep the upload progress dialog on failures
Provide error info in upload progress area

solves the "incomprehensible error message" part of #9
Make use of description_for_editor
Slightly improve appearance in small windows

* Prevent filter icons to become orphaned lines
* Prevent Search button to wrap to invisbile line
Improve image zoom

* Keeps aspect ratio
* Maximized on wider axis
Update READMEs
Bump version