Moved all javascript into their proper files.
Added basic world selection.
Extended world selection to only select from the connections of the current world.
Added image assets for highlighting of selected and current worlds.
Added sound assets and menu theme.
Added sound to game view and mission briefing elements for map GUI.
Added mission creation on map initialization.
Moved mission selection into selectWorld method for centralized access.
Totally did not sneak in an easter egg.
Changed some stylings for the dev GUI.