+ File structure re-design

+ Moved ECC functions to a dedicated Crypto class

README.md

@@ -33,7 +33,7 @@ An example code snippet:
 ```python
 from pyplayready.cdm import Cdm
 from pyplayready.device import Device
-from pyplayready.pssh import PSSH
+from pyplayready.system.pssh import PSSH
 
 import requests