Assorted Updates

[dbetz]

I've done a few things on my fork:

1. Added handling of the recon callback to indicate a connection failure.
2. Added a way for a cgi function to determine why it was called.
3. Used the "reverse" field of espconn instead of looking up the IP address and port number.
4. Added a prototype for httpdCgiIsDone.
5. Added a function to join a wi-fi network.
6. Fixed a problem in WebSocket broadcasts.
7. Probably some other stuff that I can't recall anymore. :-(

[morganrallen]

This is a pretty big PR. As it's already in conflict maybe you should consider resubmitting as multiple concise PRs.

For example, all the the typo-like, adding const and general cleanup can be a single cleanup PR. Then make a single PR for each feature you're adding. That will make this PR much easier to review, hopefully give you a better idea of what all you've done (point 7) and increase the likelihood each PR being conflict free.