Improve debugability of resource anonymous fns.

When you build up a map of routes -> resources it is helpful to have the
resource handler fn named in a way that helps finding the source.

the defresource macro eventually makes a call to liberator.core/resource
which returns an anonymous handler function, but defined in the
liberator.core namespace.

However, If we define the anonymous function as part of defresource
macro then the anonymous function is defined in the callers namespace,
this makes tracking down "I'm somehow routing to the wrong handler" bugs
much easier to debug, because the anonymous function name in stacktraces
changes from something like:

#<core$resource$fn__15560 liberator.core$resource$fn__15560@4d8afb22>

to

#<project$project$fn__41618 kixi.hecuba.api.project$project$fn__41618@2068bdce>
Merge pull request #121 from MastodonC/improve-resource-debugability

Improve debugability of resource anonymous functions.