Sending to Multiple Numbers, Multiple Content URLs, and Multiple Tags is broken

[Jeremybk]

A bug exists in the AddParameter function of the RestRequest class on line number 40. The intended purpose of this line is to add on extra values to parameters that accept collections. This is used when trying to send a fax to multiple phone numbers, with multiple content URLs, or with multiple tags. The current code actually just overwrites the parameter instead of adding to it. As a result, it is not possible to send a fax to multiple phone numbers, multiple content URLs, or with multiple tags with the current .net library. It will only end up sending the last parameter in the collection to the Phaxio API, such as the last phone number when sending a fax to a list of 2 or more numbers.