Bunch of stuff

Added user object which will store list of stats, and the users steamID.

Added some constants for steam APPID for csgo and the APIKey.

Added an APIHandler class which will be used to make the http requests
to the api.
Merge remote-tracking branch 'origin/master'

Conflicts:
	GlobalOffensiveStats/Constants/ApiConstants.cs
	GlobalOffensiveStats/GlobalOffensiveStats.csproj