Integrate security.txt with website docs. Align TOCs. Rearranged doc/index.txt and website/www/doc.txt to bring them into more agreement. Added security.txt to doc.txt so it gets picked up when building www.

#!/usr/bin/env python
from __future__ import print_function
import zlib, base64, sys
print(base64.encodestring(zlib.compress(sys.stdin.read())))