Updated code snippets to v2.2.0

[dragonmantank]

This is a prep branch for holding code that complies with v2.2.0. All standalone scripts should be updated with this PR, though a handful of "full framework" examples can be updated when v2.2.0 is properly released.

[marklewin]

LGTM, thanks

[GregHolmes]

There's a couple of minor changes I think would be ideal for consistency and/or removing unused includes.

I wonder also, if it's worth, for consistency, discussing whether to go either have use statements or not? It seems a bit mix and match at the moment with importing Nexmo classes. Some have them at the top of the file, some just import them as and when they're used.

[dragonmantank]

I wonder also, if it's worth, for consistency, discussing whether to go either have use statements or not?

For snippets that show up on NDP, we've not used use statements and instead preferred the full class name for clarity. This makes it easier to copy/paste the code. The user could always clean that up after-the-fact. It leads to uglier, but more quickly-usable code.

Historically there wasn't a way to easily show things like use or import (for other languages). Now that we can specify use statements in NDP, we should start to look at using them and see if that impacts usage.