Allow sprites to be cloned for individual units
Move assets to prepare for webserver
Initial commit of basic go webserver
Add incredibly rudimentary level based logging
Use new logger
Move SpriteManager ownership to assets

assets already owns the sprite sheets themselvs, so it makes
sense to have it own the manager as well
Grab, but not yet parse, asset info from the server

With this commit all further testing must be done with the
go webserver serving the context, as AJAX requests cannot
be made if the index.html page is opened via your file
browser
whitespace