Merge pull request #1 from qgis/master

Update 3 janv. 2013
preamble files updates and index
Update expression examples
FR: getting started translated
Merge pull request #31 from MarieSilvestre/master

fr translations from MarieSilvestre
Merge pull request #30 from NathanW2/expression

Update expression examples
Merge pull request #29 from yoichigmf/master

Web site Japanese translation from yoichigmf/master