Added wpPassthruFunction to simplfy life for certain circumstances where a function must be mocked, and needs to return a value. wpPassthruFunction wraps wpFunction by setting the return to be an anonymous function that returns the first value it is passed.
Merge pull request #4 from khadiwaa/master

Added wpPassthruFunction to simplfy life for certain circumstances where a function must be mocked, and needs to return a value. wpPassthruFunction wraps wpFunction by setting the return to be an anonymous function that returns the first value it is passe