refactored builder/factories
do not cache operation#input
replaced Params with simpler Part objects
refactoring for BaseType#child_elements

returns all child elements for a type as a flat array.
resolves extensions and adds them to the array,
but does not resolve any child elements.
renamed the OperationFactory to OperationBuilder
test BaseType#child_elements for compatibility
types now receive the wsdl instead of the schemas

turns out, using the schemas during import is too early.
so for now types have access to everything.
replaced the PartBuilder with a new MessageBuilder

this one returns Element objects which represent simple or complex types
and provides a simple interface as well as introspection features.

way to go ...
added namespaces to the new Elements
finally dropping support for ruby 1.8!
updated the readme [ci skip]
deprecated Wasabi#namespaces
added Element#form

Elements now indicate whether they should be qualified or unqualified
depending on the schema and soap specifications.

* global elements (also via @ref) are always qualified.
* local elements are qualified according to their @form attribute
  and its schema's @elementFormDefault value.
* rpc wrapper elements are qualified with the soap:body namespace.
removed Wasabi#namespaces