ep_tables3 v0.3.14

Add Tables in Etherpad-Lite

Initial project (but dead & broken) from Gideon (https://github.com/gedion/ep_tables) I decided to take over and improve it.

The plugin is available in English, French & German (Thanks to @Brom2). If you want another language, take the locales/en.json file and translate it (it's not big).

Export the tables: It only works with Html export. Text & Dokuwiki exports don't have a hook for me to handle the formatting. Other exports from others plugins must manage it in their code, but I'll gladly help if they contact me.