Add ability to filter generated types by service names.

- Added tests for filter and config parameter.
- README modified.
Improve documentation.
Refactor type identification.

Remove need for finalTypes variable and named keys for a simpler recursive function.
Replace methodNames with operationNames.

This goes better with SOAP terminology.

Also refactor functional test a bit by using and expanding existing class method assertions.
Merge pull request #192 from kasperg/ivol84-feat_filter_soap_methods_3.x

Filter SOAP operations