Remove our dependency on Catalyst::Action::REST. We were only using it

Remove our dependency on Catalyst::Action::REST. We were only using it
for serialize / deserialize, and we might as well do it ourselves.

We would use Data::Serializer, but its YAML is YAML.pm, which just
doesn't seem to work... when Data::Serializer::YAML_XS shows up, we'll
switch to that.

Also broke the tests out a bit, and added a test for what happens when
the action you invoked crashed.