on_set_avatar_button_clicked default folder

[xerxas]

in vcard.py in function on_set_avatar_button_clicked we should add something like this:

dialog.set_current_folder(os.environHOME?)

So that the user chooses his avatar in his home (/usr/share/gajim/src/common have no image and is probably pwd at runtime)

[asterix]

done in [5667]

[nk]

userprofile is not good default for Windoz.

http://windowsxp.mvps.org/usershellfolders.htm

I'll wrap those in a happy helper func, so we can finally get the most out of Windows

[nk]

[5668]