Replace __call with explicit method declarations
Replace __call with explicit method declarations

This commit will replace the __call magic with explicit method
declarations for faking any of the supported HTTP methods.

As a API, it's preferable for the API to be discoverable. Having
explicit method declarations help IDEs to list the class methods when
writing tests.

manhtai/slim-test-helpers,there4/slim-test-helpers,PinZhang/slim-test-helpers,hochanh/slim-test-helpers