Add TP for embedded files

[rojepp]

It would be nice if a TP for embedded files could be added, so that you can get intellisense completions and compile-time checking of file names.

It may be a bit problematic, in that a TP doesn't see the project system, and can't really load the assembly that is being compiled. :) The simplest way to do it is probably to just scan the fsproj file for embedded files.

The properties could be of byte array or stream?