French language corrections and additions.

Added missing french entries and corrected ones in spelling, accuracy and formalism.

As for "navigation" vs "cartographie", basically "cartographie" is map drawing, while navigation is actual use of the map to orient yourself.

To whoever whom would be tempted to write nord with a capital ;-)
http://fr.wikipedia.org/wiki/Usage_des_majuscules_en_fran%C3%A7ais#Points_cardinaux
Merge pull request #886 from 11RDP-LoupVert/patch-12

French language corrections and additions.