Added use for failing libraries

We had an issue with one of our build jobs with your module which was causing some failures.  It turned out that via some combination of other prerequisites IO::File hadn't been loaded by anything else.  The failures were caused because your module relies on them but does not use/require them and as such it was dying.

I've added the relevant uses, they could be turned into requires if you so desire.

I would have written a test for this but I'm not sure of an easy way to test compiling an XS module and there were no examples in the test directory I could compare with.  If you could give me some pointers on writing a test case for it I'm happy to write one.

When I examined the code more closely I found a couple of other modules which may not neccesarily be loaded before your module which I also added as uses.  The list is below.

I haven't included a version bump with this pull request so you may need to do that if you merge and push to cpan.

File::Path
File::Basename
IO::File