This script can be used to parse and generate PSSH boxes. This
serves two purposes:
* Parse PSSH boxes into a human readable format.
* Take several arguments to generate PSSH boxes.
This is also able to parse Widevine and PlayReady PSSH data and will
print the parsed data instead of the data as binary. This can also
generate Widevine PSSH data instead of having the PSSH data passed
as an argument.
Change-Id: I245bd9abf79a259f6fda01d1fc0489b4a4a73db5
Jacob Trimble