Major changes to Constants.h & minor changes to RiotDataManager

Discovered that some regions must be called with global.pvp.net
Accordingly, first occurance of {region} was replaced with {server}.
apiURL() now takes in query strings, but they must end with &.
Some logic of apiURL changed accordingly.

Removed RiotDataManager's methods and instead made the dictionaries public.
Currently not thread-safe and data integretiy not retained.
Might be a problem considering NSURLSession works in the background.