Implement Product Configurable API.

* Needs custom  magento_webservices module (available in Github)
* https://github.com/zikzakmedia/magento_webservices
Updated README
Updated Catalog Product Attribute Info API

* Note: Needs updated Magento Webservices Module
* https://github.com/zikzakmedia/magento_webservices
Implement ProductConfigurable:setSuperAttributeValues API
Implement create attributes options API

* useful to create manufacturers for example
Pepify the code
Product Attribute. Remove Option
change API path, this works on Magento 1.7
add note about custom plugin required for ProductConfigurable
fixed multicall
Rename createOption to addOption

* `createOption` is called `addOption` in Magento
* deprecate `createOption`
Implement ProductAttribute API

* add methods for `create` and `update`
* add methods for attributeAdd and attributeRemove
Make ProductImage.create signature match Magento

Previously this was a layering violation. There's no reason for
`create` to change the argument signature of just this method,
base64 encode the image, and detect its mime-type, especially
if `update` does not do any of that .

The calling code should be responsible for encoding and mime-type
detecting in both cases, and both methods should match the Magento API.
Cleanup the README file

* Convert to ReST syntax
* Update the code examples
* Add LICENSE