fix (content-type) : files are now uploaded with content-type

[pierredeman]

By default, content-type is "binary/octet-stream". On web applications, when accessing a text file with a "binary/octet-stream" instead of "text/plain" content-type, most browsers/clients download files instead of display it.

[pierredeman]

Of course, it's done for detected and undetected content-type. I found no case for IOException.