Allow specifying name of resource identifier parameter
Merge branch 'feature/custom-identifiers' into develop

Start of #42

Allows specifying custom identifier parameters for a resource. Does not yet
address URL generation, however.
Synced changes to identifier name configurability with ZF2/develop

- zf2 develop branch uses setIdentifierName/getIdentifierName; made this
  sync with that so I can remove it later.
Merge branch 'feature/custom-identifiers' into develop

Sync with zendframework/zf2 develop branch
Integration tests for child resources

- Demonstrates that parent resources work as expected
- Shows failures when rendering child collections and resources
- Fixes issue with injectSelfLink(); was not using configured identifier
  name!
Ensure route matches contain correct matched route name
Emulate URL helper factory

- Factory injects the route matches stored in the application MvcEvent;
  added code to inject the route match manually after we match via the
  router.
- Interestingly, everything "just works" at this point.
Merge branch 'feature/child-resources' into develop

Adds integration tests for child resources:

- Fixes issue with injectSelfLink(), which was not using the configured
  identifier name (this may be the missing piece, actually!).
- Demonstrates that both parent resources, child resources, and child
  collections receive the appropriate links in their link collections.
Merge branch 'develop'

Adds the ability to modify the resource identifier name (using
`setIdentifierName`) so that a value other than "id" may be used (this parallels
a similar PR on ZF2, for release with 2.2.0). That identifier name will be used
to generate links to resources.

Also adds some integration tests to demonstrate usage of child resources.