Various improvements and bug fixes

### Fixes
* folder was still spinning when all children were actually uploaded
* (tags) using "down arrow" key in empty autocomplete tags list was triggering an error
* (tags) when autocomplete tags list was empty, borders were shown (resulting in pixel imperfection)

### Improvements
* number of tags displayed in autocomplete is now limited (to 10)
* a view is used to retrieve files to generate zip
* a regression test now checks that the binary is actually removed when a File is removed

Closes #153, #154 and most of #158.