New ResourceList class, refactor resources to use it

Added new ResourceList class. Implements backend pagination to the API. 

Add static get<Resource>s methods for each resource. Returns a ResourceList with the appropriate resource objects.

Refactored RestResponse to include the Link headers. Parses the Link header into first, previous and next strings.

Small refactor of the BandwidthRestClient to implement generic get method. This is the future vision of the client, e.g. a clean abstraction of the http methods with conversions happening by Utils classes

Added Utils class for basic conversions

Refactored Examples to use new lists

Still left is deletion of the plural resources, e.g. Applications