[Gvsig_english] "Desktop" should not be hardcoded in English during installation

[Moritz Lennert]

Hello,

The installer installs the launch icons in the $HOME/Desktop folder. 
However, users may use a different language and their desktop might thus 
be designated by another folder (e.g. $HOME/Bureau in French). If 
possible, the installer should detect this and install the launch icons 
there.

Moritz