Automatic download of language files

[mvlcek]

- Check for updates to Plugins

The problem with that is that currently there is no way to find the plugin in Extend - in GetSimple you have the plugin's file name (the plugin name) and it's title, as specified in register_plugin - in Extend you just have the name given by the developer on upload (which can be different from that in the plugin) and an ID.

I suppose, on upload of a plugin by a developer Extend would have to unpack the zip, get the filename(s) of the php files and store them, so that they can be accessed by filename via the API. Shouldn't be too hard.