Added ability for proxy to look at both application root and in same fol...

Proxy looks in the application's root folder for its config; if it does not find the config file, it looks in the same folder as the proxy itself.

This change supports the use case where the resource-proxy repository is brought into other repositories for use as the latter's proxy program. By using the search order of root first, then co-located with the proxy program, it's possible for the resource-proxy repository to be brought in as a submodule and to not need any editing to its config file with each update:  the destination app's root-level config overrides the one in the submodule.

It also supports the concern of issue #41 both for compatibility with the Java and PHP flavors and for the case where the destination app is missing a root-level config file.