**This commit removes Base64 (and Flash) support**

This commit converts websock.js to used Typed Arrays for the
receive queue (and tweaks rfb.js to ensure that it continues
to function, since only Firefox implements
`%TypedArray%.prototype.slice`).  Base64 support was removed
to simplify code paths, and pave the way for using Typed Arrays
for the send queue as well.

This provides two advantages: first, we allocate a buffer ahead
of time, meaning the browser doesn't have to do any work dynamically
increasing the receive queue size.  Secondly, we are now able to pass
around Typed Array Views (e.g. `Uint8Array`), which are lightweight, and
don't involve copying.

The downside is that we initially allocate more memory -- we currently
start out with 4 MiB, and then automatically double when it looks like
the amount unused is getting to small.

The commit also explicitly adds a check to the compacting logic that
avoids calling the copy functions if `_rQlen === _rQi`.

This commit introduces an alternate implementation of the zlib
decompressor based on Pako (https://github.com/nodeca/pako).

Also, update nova-novncproxy to import websockify instead of wsproxy.

Add wswrapper info to utils/README.md and docs/TODO. Remove innacurate
info from docs/notes.

Looks like disabling web-socket-js debug messages by default that we
get a minor speedup.

Python proxy should support both 75 and 76 (00) modes. Also, update ws
test to more reliably hit the WebSockets ordering/drop issue.

The purpose of the code is to be incorporated into other web projects
(whether those are free or not). AGPL prevents combination with other
HTML and javascript that is under a weaker (or proprietary) license.
Better would be a lesser AGPL, but there is not GNU standard for that.
So LGPL-3 meets most of my requirements. If somebody modifies the
actual client code and conveys it, then they must release the changes
under LGPL-3 also.

Add some implementation notes in docs/notes.