Add Voice API

[dstotijn]

This PR adds Voice API endpoints to the PHP client.

[selirah]

Is there a way you can add contact through the PHP API?. Because when I was testing that I got the error "You are not authorized to perform this operation"

[dstotijn]

@EddieSeli: Is that related to this PR? Otherwise better suited for #45, which deals with contacts and groups.

[selirah]

Okay, thanks. Will check that out

[sotoz]

It could be very handy to add to the example how to save the wave file locally.

[dstotijn]

Done

[sotoz]

Also here, how about outputting the actual content of the transcription?

[dstotijn]

Done

[Dirk94]

Client->voiceCallFlows()->getList() returns a BaseList object. BaseList expects the API to return

{ 
  "offset": 0,
  "limit": 20,
  "count": 1,
  "totalCount": 1,
  "links": {
    "first": "url-here",
    "previous": null,
    "next": null,
    "last": "url-here"
  }
  ...
}

However the voice API returns

{
  ...
  "pagination": {
    ...
  }
}

Therefore the BaseList attributes (offset, limit, links, etc) are null and the pagination attributes are ignored.

[dstotijn]

@Dirk94 Pushed a fix for this. Because Voice API currently has different pagination params (e.g. no offset) and also no links param, I've introduced a new BaseList for Voice specific resources.

[samwierema]

@Dirk94 tests are still failing. It seems like the PR uses the new array notation []. Can you fix?

[samwierema]

@dstotijn can you do review of the changes since this week?

[dstotijn]

OK, looks good!