Error message improvments

[Tumulte]

Hi,

I've noticed few stuff in the error messages that can be easily changes for a better usability.

"Sorry, I don't support that file type :("

I'll take this example only, but the tips apply to other :

• Avoid the anthropomorphism ("I don't"). It weakens the feeling of control (i.e. : I can solve this error, cause it's only a machine).
• The error message is not the place to be verbose, the user want to understand what's wrong right away. e.g. : The "sorry" and the ":(" are unnecessary
• It lacks of information : what did I send, what's supported ?
• It comes to late (you have to fill the form all aver again... and ajax check would be in order)

Therefore the message should come right after selecting the file and should look kike this :

"oga" support is not enabled
(and bellow, i.e., not in red : )
filetypes enabled : jpg, png, gif, mp3, wmv

[Tumulte]

"is not enabled" is important, cause it gives a hint that it can be customized.