Update and rename systems/coruscant.xml to systems/legends/coruscant.xml

Sources include:
http://starwars.wikia.com/wiki/Coruscant
http://starwars.wikia.com/wiki/Coruscant_system
http://starwars.wikia.com/wiki/Atmosphere#Type_I
http://www.theforce.net/swtc/units.html