Plugin Manager

[bobbens]

With plugin support and the naev-plugins repository online. We need some sort of plugin manager before plugins can become a widespread reality. There are multiple approaches to do this:

1. Standalone python (or other language) application that manages it externally. Could be potentially started from Naev itself.
2. Lua script to manage plugins from Naev itself directly.
3. Integrate plugin management directly into the C stuff engine-side.

I do think a standalone app that can be called from Naev is probably the best and most flexible option. It would allow us to use all sorts of http libraries and such from python without having to link and add lots of API to libraries. It would also allow managing plugins without starting Naev so you don't have to restart. Probably a good first project for someone who is interested in writing up a practical python app :)

[BlackFrame42]

Here is a prerelease of a plugin manager: https://github.com/BlackFrame42/naev-pm/releases/tag/0.2.1
Currently, Naev has to be restarted to detect the plugins installed by the plugin manager.