Ability to more easily support more mobile phone providers.

At present SmsPie only supports Meteor (Ireland). SmsPie should provide a simple solution to add support for other mobile phone providers, for example, via a providers file. This inherit from an interface and must simple implement the required methods for the new provider. The file would then be named by country code and provider name... For Example: ie-meteor.py (for Meteor Ireland) or ie-vodafone.py (for Vodafone Ireland) or uk-orange (for Orange United Kingdom).
The provider file can then be dropped into the providers folder where it is automatically detected and can be used.