Adding a unit test to "file_io.rs" to test file operations.  One test compiles but doesn't successfully run yet.
One unit test for "file_io.rs" successfully runs (file not found) and 'letstalk.rs' now pulls the Vector of FriendInfo structs out of the returned IoResult.
Merge branch 'master' of https://github.com/ZuhlkeLjubljanaEms/letstalk