CL: Mongoose Web Server: Digest authentication: Fix nonce validity check (expired nonce or nonce from the future did not cause the the check to fail)
CL: Mongoose Web Server: Digest authentication: Fix nonce request value; it worked before because nonce validity check was broken as well
CL: Mongoose Web Server: Digest authentication: Add `nonce` argument to `mg_http_create_digest_auth_header()`: clients should use the value received from the server's authentication request.

Resolves https://github.com/cesanta/mongoose/issues/809

PUBLISHED_FROM=5e59f90ed6b2a4311ed6763159da81c2aaf6af4c

CL: Mongoose Web Server: Websocket: Respond to Ping with Pong
CL: Mongoose Web Server: Websocket: Properly close a connection with Close frame (in response to a client's close and when protocol failure is detected)
CL: Mongoose Web Server: Websocket: Fix support of fragmented messages
CL: Mongoose Web Server: Websocket: Add support for control frames interjected in the middle of a fragmented message

PUBLISHED_FROM=e2b3794aaacc64633540c493194cccc62afa2077

PUBLISHED_FROM=2c176091ffb6c7c5cfe8ea4f05b6109e00b33383

PUBLISHED_FROM=1bfc6e332f56b68eb6155bb729a97a0d8d5a316c

PUBLISHED_FROM=f97569ae2f31ab94ce4875eae4d0a198f719c388

Change the API to heap-allocate the string and get rid of a bunch of fat stack buffers.

PUBLISHED_FROM=c793dc64a9a044a9769d92ea16859f5d704a2181

PUBLISHED_FROM=1803e726eee7bb64496d70389655083eb70257ab

PUBLISHED_FROM=efa9cc3aaf0c5ae8841e029370f882b615cebf1b

PUBLISHED_FROM=e69e298a51dbe0f9c47184169ecad06eef0676fc

Also amend api_net.js to use returned length.

PUBLISHED_FROM=38e15f9587edf28049c5b9e5f126b4db159910e8

 - Move keep alive management up to the Mongoose library
 - Only outgoing control messgaes should reset keepalive timer
 - Add unit test

https://forum.mongoose-os.com/discussion/1155/mqtt-keep-alive-compliance-issue

PUBLISHED_FROM=f86e30744ded53a6f7f96afec066b4ff3b4372c0

Rationale: this is the optimisation to make JS FFI-ed API
work nicer. We don't have strucuture introspection now,
and do not generate offsets automatially. Thus, using a
stable well-known location of the parsed message body is
better, in case of number of HTTP headers macro changes.

PUBLISHED_FROM=55bf25ac77060a9c81dfecd6601f037562530801

PUBLISHED_FROM=533e134a48e0fca55509c3eb16b0a6b64c1188e8

Remove the specialized URI parser, clean up code a bit.

Fix parsing of URIs with IPv6 hosts (http://[2001:2:3::4]:567/)

PUBLISHED_FROM=968ad97585d928123106ce3828920ee073113f83

PUBLISHED_FROM=257deff5ea20302627e77a0f29cf2359276a41d4

PUBLISHED_FROM=56fdeaf4965ef26c398267c8656735bb52e45085

PUBLISHED_FROM=10772301ef115c31ada3521ff4235c33a421b782

PUBLISHED_FROM=29a204c2c7f35724b6f1e8435edb94869da2362c

PUBLISHED_FROM=93fe1cc2c5e2513509511a81e5919cbd37056b10

Frees up a bit of ram on ESP

PUBLISHED_FROM=0ea046cc63704481bca138b3096937669b94733d

PUBLISHED_FROM=b5b12cdf4273f21dbcdac9bfb6a06063152914c9

PUBLISHED_FROM=1bdacf793b35ebe70d0a3a9d64260dd2bd135c73

PUBLISHED_FROM=35e8f18aa611b45c271d0178d9197291bfa9726d

`mg_mqtt_match_topic_expression()` and friends are public now.

So far, only `#` is supported.

PUBLISHED_FROM=20c031bcf34be84771c4a9c456318634eb9a517c

For both OpenSSL and mbedTLS

PUBLISHED_FROM=0bfd5f128b4c4c062cb6f0ca0da9b30790aa8bf8

PUBLISHED_FROM=f0fe58c9f01ef0c7b491ed0e5f51b983e4119507

PUBLISHED_FROM=7864ffa26cb553f5d4a93248f67c288327ec23b0

Optional specification of SSL/TLS cipher suites.

PUBLISHED_FROM=e8968c6c7a92f10514d3ee575c2fb9be862e6cf8

Also fixed a memory leak on reconnect: previously, each reconnect was
creating a `struct mg_connection` which was never reclaimed

PUBLISHED_FROM=eefdcf557e032ac81d5ed3aba55ac912e400148e

PUBLISHED_FROM=cccd28ef43ec4e08fa52340ce78bda10db5ac27a

PUBLISHED_FROM=182c43c3bd82190cb816c8ebaddccc13a94950d0

PUBLISHED_FROM=0454cdeec5c7120eb4bf905fdd5b7abdcb4003c2

PUBLISHED_FROM=196199fd02ec9b20d1e76d1414bfafa624f9ebce

Currently only OpenSSL API impl, but the plan is to add more.

PUBLISHED_FROM=c85b26fa2312047768bdcf3eca583e60862aba90

PUBLISHED_FROM=f554cc63dfea12455fe5e428c6ce5f3152774f8e

PUBLISHED_FROM=39a1c2a271c5cd961670e11c830105c17ba0b2e4

PUBLISHED_FROM=f03b963aaec02574e47c28ee8033551440b94f2d

PUBLISHED_FROM=2b82f3793b3c6d0cf1266e4cc0e67930f43002c5

PUBLISHED_FROM=46496c2d5340a0bbe4fe1c6c9ff187bc65d2d35f

PUBLISHED_FROM=cded8f36e2833e7c256ba6cbca0ebf1f6012dee7