Module schemefs - RMoX scheme-based file-system support

RMoX scheme-based file-system support. This provides support for 'scheme' based file-systems, which may not be real file-systems as such, but can be accessed in a similar way. E.g. "http://server/path" or "tftp://server/path". A key difference is that schemes may not support capabilities like 'list directory', or may not even be persistent in any meaningful way.