UTF8 normalization of name in IPFSLink

I do not see any mention of names inside IPFSLink being normalized. It [seems this is not done automatically by Go](https://blog.golang.org/normalization). But this is pretty tricky in file-systems. For example, Mac OS X filesystem has different default UTF8 normalization than Linux. I had issues in the past with this when mounting network file-systems. That I could end up with two files with visually same filename, but just difference in UTF8 normalization.

I would suggest that internally, in the network, all link names are normalized to the same UTF8 normalization.

Then, when you mount IPFS into the file system, those links are converted to the host normalization.

Start by locating IPFSLink and reviewing how link names are represented and used across the network and filesystem mounting paths. The issue does not name files or tests; research must first establish the normalization rule and the host-specific conversion behavior. Done would require consistent network names and correct conversion when mounted on different filesystems.

Written by the indexing model from the issue text.