Change OperationElement.prototype.describe to check for existence of input/output
before adding them to the description. Unit test and sample WSDL file included.
Merge pull request #260 from mbroadst/fix-describe-on-single-operations

Fix describe on single operations
Update CONTRIBUTING.md
makes node-soap ua matches package.json version
Merge pull request #263 from nw/feature-useragent

makes node-soap ua matches package.json version
Fix for issue # 204.
Merge pull request #269 from ankush-garg/namespBr

Multiple Import Schemas and Namespaces.  

Fixes #204.