Change authData into a normal variable and add getAuthData()

authData is not a global variable, instead the function getAuthData()
was created that initializes the variable. "myProfileURL" and "cookies"
were added as fields to authData. Both variables depend on other fields
of authData anyway. Function generateCookies() was included in
getAuthData().
Replace os.system('pause') with multiplatform raw_input()
Switch to multiprocessing
Change file and folder structure, add libsteam_api for other OS