Added server version to HTTP status reply
Added client-plugin interop system for passing messages between client and plugin
Replaced chat in/out files with interop functionality
Server now runs a dedicated thread for sending outgoing messages
ClientData and PluginData are now sent via interop messages
Plugin updates now use interop messages
Plugin updates are now divided into primary and secondary updates
Client now explicitly sends the activity level to the server
Client now sends the update interval to the plugin
Players can now be shown as idle while in-flight
Screenshot sharing now uses interop messages
Screenshot viewer now displays the player/ship of the current screenshot
All UDP messages now included the client index
Added /ping command
Updated dlls to KSP 0.19.1
Add server info message for displaying in the http status reply