Internationalization, french translations

Closes #12 (closed)

Uses the LANG global variable to translate everything.

Covered languages:

• english (default)
• french

To add additional languages, simply populate src/translations/<language_code>/LC_MESSAGES/install.po with translations, copy the line with msgfmt ....

To change language, you can either change the overall main language or run the script with:

# locale -a | egrep 'en|fr'
LANG=fr_FR.utf8 ./src/install.sh