Add support for Virtual Paths as part of the application structure

If you have a directory structure with shared assets between projects using IIS' Virtual Path feature, Rejuicer currently generates invalid file names.

Given the following project structure:
```
CommonAssets/
  Content/
    Common/
        style.css
WebApp/
  Content/
    Common => CommonAssets/Content/Common (Virtual Path)
```

Rejuicer now generates a file name like `/monAssets/Content/Common/...` or `/tent/Common/...` (skipping parts of Content or including parts of the path to the CommonAssets project) if the folder names aren't the same length.