Galette

Currently, translations are quite simple; only translation domains are used (one for Galette core, and on for each plugin).

Some features are missing and should be implemented:
- plurals,
- contexts,
- comments.

Plural support is self explanatory :) Contexts can be used to translate a same string in different contexts; and translation comments can be used to inform translators of the replacements, or some rules to follow on a particular string.