Replace HPE copyright with DMTF one in Python source files.

20190613 v1.1 supoprt empty property (#4)

* Redfish Schema C Structure Generator v1.1
* Support RedfishCS_Type_CS_EmptyProp for the property declared as Empty Property ("properties": {}). Only support below types of JSON value, the JSON object nested in the property is not supported,
 - JSON type string
 - JSON type number
- JSON type integer
* Some bug fixes.
* Change copyright strings.

* Update README.md.

Initial version of Redfish JSON to C structure generator. (#1)