If file path can not be mapped to a local file, allow the engine interface to load it via its own means

[gwomacks]

For example, xdebug allows the ide to fetch source for a file using the source command

[ahnbizcad]

Would this be the same thing as using filemaps as fallback, like how most routers work?
In other words, "If the remote file path does not have a corresponding file in the local path, attempt to find it using the next remote-to-local path-matching rule"

For my case, I have code from various folders dynamically aggregated to a single folder in the remote file system. So my local code still remains in multiple folders (why do I do this? Because when I build multiple ecommerce apps, I can have code that affects all stores, and code that affects stores individually).

I want to be able to do something like this in php-debug:

"php-debug":
    PathMaps: [
      "remotepath;localpath"
      "/remote/fun;/local/first/fun"
      "/remote/fun;/local/second/fun"
    ]
    ServerPort: 9000

So I want it to look in /local/first/fun first. If a corresponding file exists in the local, good, stop there.
If it doesn't exist, try finding it using the second rule, /local/second/fun, and so on until the last rule is attempted, or it is found.

With a codebase organized the way mine is, with common vs app-specific code separated out, this feature is critical to using the debugger conveniently.

Thanks for all the work so far. =]