Fix OAuth url issue and revert User property behaviour

 * Reverted User property behaviour to not initialize itself, there are currently no other ways to check if a User has been authenticated.
 * Fix a URL issue when OAuth token is used.

NOTE (@Erok21): Your OAuth code is broken, as it will use incorrect endpoints for certain API calls. When authenticating with OAuth, you have to use different endpoints for certain resources (like /me): http://www.reddit.com/dev/api

The endpoint issue is not fixed in this PR. Not sure what the best way to implement it would be.