Hard link name (and link refactoring)

[bbengfort]

When a hard link is created the name isn't modified, meaning that there appear to be copies of the file and in order to remove the hard link, the referenced name must be removed, which is impossible to see.

[bbengfort]

So in order to fix this, I attempted to create a type Link that wrapped a Target (which was a pointer to an Entity object) such that all the FUSE methods passed through to the *Target except for the Path() and String() methods which referred to Link.Name.

This did not work.

First - I had to copy and paste every single method ... so it was verbose. Second, the Readdir() function uses GetNode(), which returns the *Target.Node and therefore the original name, so it didn't even fix the problem!

I was probably on the right track with this, but some better wrapping is necessary. We also have to update the filesystem to count links a bit better, and to manage the Attrs.Nlinks counter. We also have to update Readdir() to do better name checking.

Finally, I also want to make sure Symlinks are implemented as Link objects or have a shared link structure (even though they are just files). So some thought needs to be put into that.