The ari_client node legend is incorrect and highly confusing; crashes

[bogorad]

First, thank you for your effort! It was very hard to get it working due to a lack of documentation and various quirks of Asterisk itself, but once it's working, it's a godsend.

Problems:

1. Node-red crashes if asterisk_ari can't connect to the configured host:port.

2. The legend in the ari_client node editor is highly confusing! It should say "Stasis() app name", not "SIP Password"!!! Cost me a couple of hours ;)

3. A link to Asterisk ARI documentation with the relevant dial-plan setup would help:

https://wiki.asterisk.org/wiki/display/AST/Getting+Started+with+ARI