[WIP] Basic version of song importation work (but I do not think it compiles)
[WIP] indexes work again
[WIP] Songs are now parsed using PlasTeX
[WIP] Song languages work
[WIP] Managing titleprefixwords
Deleting useless stuff (and preparing 'sort' content plugin)
[WIP] Managing authwords
comment
Sorted out configuration defaults (between hard-coded defaults, templates, and configuration files)
Fix case where configuration file contain no content keyword at all