a script to run spectool_raw as a WebSocket server.

WebSockets can be simple. This server is just a little shell script (bash, not POSIX shell unfortunately) adapted from this: https://gist.github.com/apk/2414478

Requires tcpserver or similar to expose it to the network.

Also requires openssl (the command line tools).
add a live view that uses WebSockets.
make live view faster by refreshing periodically.
keep live view from bogging down by throwing away the oldest samples.
rename dropdown, call it 'data source' now instead of 'log file', since live view is an option.
fix frequency band highlights in a couple cases.

fix: frequency band highlights should extend the full length of the spectrum view, even if there isn't enough data to fill it. provide a dark background underneath in this case.

fix: don't clear frequency band highlights when the live view updates.
fix errors on first few non-data lines from spectool_raw
fix issue where live view would keep adding spectrum data if we switched back to a file. shut off live view at that point. also, show websockets error code on close.
move dropdown to navbar. show useful alerts.

Save vertical space by moving the Data Source dropdown up into the navbar.

Show an info alert when a file is loaded.

Show an info alert in live view with number of samples collected so far.

Position the alert so hiding / showing it doesn't move other page content.
data source dropdown: add some separators.
resize frequency band highlights after rendering, so that they always fit the canvas.
also, the frequency band buttons should stay toggled when loading a new file.
clean up bootstrap alert code.
square up the alert. add a label for the data source dropdown.
add daemontools services for the httpd static file server and the websockets server.
new screenshot of live view
document live view. better docs all around. add 'serve-static' and 'serve-full' make targets.