change export proxy on .profile or /etc/enviroment

[ailtonbsj]

This can be tested with app kstars downloading an image.

[ailtonbsj]

Need to test if the use of http in all variables will work on kstars, google-earth and apt

export http_proxy=http://proxy.exemplo.com.br:8080
export https_proxy=http://proxy.exemplo.com.br:8080
export ftp_proxy=http://proxy.exemplo.com.br:8080
export socks_proxy=http://proxy.exemplo.com.br:8080