force string request names

This forces requests to always have string names.  This helps ensure
requests will always be routed to handlers whether they were created
with string or symbol names.

Note, redding/sanford forces service handlers to be routed with
string names.  This ensures you won't get a 404 b/c you defined
the handler with a symbol name but made a client request with a
string name.

Related to redding/sanford#96.
Closes #22.

@jcredding ready for review.