Changed Factory pattern to singleton pattern #35

Factory pattern was used to instance only one class, singleton pattern
is more adapted for that and handle only one connection to the soap api
Created factory class to handle web services #35

Creation of a factory class to provide the correct web service. It's now
possible to create new webservices class and add it easily in the
factory class
Fix typo #35

Fix typo in documentation
Split Webservice class into multiple classes #35

Splited the Webservice class in other classes to make it more readable
and more object
Singleton class MagentoSoapClient #35

MagentoSoapClient is now a singleton class to prevent multiple
instanciation of it, rather to store the instance in a var and verify if
this one is null or not.
Added a factory class for webservices #35

WebserviceGuesser is now a factory class, it to provide the
correct instance of webservice when needed
Writters's compatility with the new webserices #35

Made the writter compatible with the new webservice
Made the processor compatible with webservices #35

Processors are now conpatible with the new webservices
Made the cleaners compatible with webservices #35

Cleaners are now compatible with the changes
Mappers's compatibility with changes #35

Mappers are now compatible with new webservices
Normilzer is now compatible with webservices #35

NormalizerGuesser is now compatible with the factory class of
webservices
Removed the webservice class #35

Removed the webservices class since it transformed into an abstract
class.