Plugin system roadmap

Notes about further developments of the plugin system for LimeSurvey.

New events does not have to be written down here. Just add them to the events page.

Features

 * config.json - already included in develop branch (3.0.0)
 * version
 * requires/dependencies
 * possible to configure how the plugin is shown in plugin manager (buttons etc)
 * localization of string in plugin => with config.json + https://bugs.limesurvey.org/view.php?id=12086 idea
 * Automatic updates: "A new version is available for this plugin"

Bugs

 * Plugin manager loads all plugins, active or not. Should only display them in a list, not load.
 * Multi-lingual settings for admin https://bugs.limesurvey.org/view.php?id=11666 (really hard to have a good fix here ... : maybe break API )
 * Remove empty classes? But mark as deprecated first?

Potential features

 * Order / dependance of plugin : see https://bugs.limesurvey.org/view.php?id=12127
 * White-list of potential plugins to install; search for plugins inside LimeSurvey