add attention-messages when donwload failed

[Lukyn]

It is not bug but wish. There is no specific information why download-process failed. Just I get information 'disconnected', but I don't know why. In this case I am clicking and clicking and tearing my hear from my head :-).
e.g.:
I can't download file because:
 - I have already this file in download directory.
 - I haven't enough free space on disk. It is quite tricky, because the file is still in queue and the file is downloaded again and again to infinity.
 - source user canceled connection

Thanks for consider.
Lukas.

[Razzloss (razzloss)]

True, error reporting in many cases is either non-existent, confusing or you just have to be quick (e.g. the error is shown in some statusbar as long as the next message overwrites it).

--RZ