Option to stay on same file system

[agriffis]

This is based on #89, to fix #8, with the addition of changes from Andrew's code review.

I'll also try to fix the problems reported by appveyor. Zero prior experience with Rust, so this is all random stabs

[agriffis]

I'll try to keep poking at this, but I'm completely new to rust, so it might take a while to figure out the build errors reported by appveyor

error[E0308]: mismatched types
   --> src\lib.rs:493:39
    |
493 |     windows::windows_file_handle_info(path)
    |                                       ^^^^ expected reference, found type parameter
    |
    = note: expected type `&std::path::PathBuf`
               found type `P`
error[E0308]: mismatched types
   --> src\lib.rs:493:5
    |
492 | fn get_device_num<P: AsRef<Path>>(path: P) -> std::io::Result<i32> {
    |                                               -------------------- expected `std::result::Result<i32, std::io::Error>` because of return type
493 |     windows::windows_file_handle_info(path)
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected i32, found struct `winapi::um::fileapi::BY_HANDLE_FILE_INFORMATION`
    |
    = note: expected type `std::result::Result<i32, _>`
               found type `std::result::Result<winapi::um::fileapi::BY_HANDLE_FILE_INFORMATION, _>`

[agriffis]

Looks like @mckaymatt is working on the build errors in #89 so I'll close this out