Cat 2691 xml classes bandwidth sdk

Hi,

I have added supported in the sdk for the elements supported by our Baml technology.

Basically those are helper classes that helps the sdk user to generate xml from pojos.

In the package com.bandwidth.sdk.xml there is:
Response class: base class for xml creation

In the package com.bandwidth.sdk.xml.elements you can find all tags we support

In the package com.bandwidth.sdk.exception, you can find the exceptions raised during xml processing

And in the test node at package com.bandwidth.sdk.xml you can find the class TestResponse that has lot of examples of DOs and DON'Ts.