Simplifies fetch_url, and hides whether a passphrase is used for a note from
the server operator.

	modified:   __init__.py
	modified:   note.py
Re-added Zlib compression
Dynamic duress key generation and decoding

Build a dynamic duress key if the user supplies a passphrase. Do not store the
duress key to disk- instead, build it from the URL (nonce). This requires adding
one more line to the dconfig.py configuration file.
remove unnecessary logic from main.js for duress key
add tooltip for duress key on /post
remove unnecessary logic for duress key
remove unnecessary logic for duress key support