The MetadataExt functions are nightly-only right now so we need to call
the windows api ourselves to get the device number. The winapi_util
package has a nice wrapper to do this for us.
The get_device function doesn't appear to be used anywhere so I removed
it.
New assert_cli library requires we cast the param passed to 'is()' as
it can no longer cast implicitly. I am guessing this is because it is
due to confusion between whether to cast to u8 or str
Advised to use walkdir by burntsushi as using recursion on file systems
can blow the stack.
walkdir is slower but allows the code to be cleaner and more reliable
Also experimented with ignore but locking the hashmap resulted in
similar performance to walkdir but with much uglier code.
