Use OSGi bundles

[csmith]

I think we should look at switching DMDirc to use an OSGi framework for both the client itself and for plugins.

The OSGi framework could replace a lot of stuff we do ourselves, such as:

• Dependency management
• Requirements (OS, etc)
• Meta-data (version, name, description, author)
• Classloader management
• Dynamic loading and unloading

It would also support some new features:

• Dependency networks rather than chains (e.g. plugin X can pull classes from A and B)
• Security (isolation, permissions)
• Optional dependencies
• Localisation
• Proper lifecycle management

As well as all that, it allows us to split the client up more into separate components without being a pain in the ass, stop bundling all of our dependencies explicitly in a giant jar, share libraries between plugins, etc.

[csmith]

I think it will be quite easy to migrate as well. We can ship plugins with both their existing meta-data and the OSGi meta-data and load them either way.

[csmith]

Using OSGi and proper services for plugins would mean we could upgrade to Dagger 2 as well (as we can stop abusing it for plugins)