Twilio API update

This plugin release updates the included Twilio library to version 6 of their API. The version 5 API has been depredated and is no longer supported. There are some minor code changes required by the new API. No new functionality in this release.

There is one small bug fix that suppresses an exception report when certain errors are returned by the Twilio API.

Release 7.0.1

This is a minor update. This release embeds the Twilo library in the plugin so it doesn't need to be installed separately. This release also enables multiple files to be sent in one MMS message. Just list multiple source URLs, comma separated, in the action. Twilio has a max of 10 items per MMS, but this is not enforced by the plugin.