Directory symlinks

fuse: allow setting mtime to earlier time

fuse: Fix readdir when directory does not fit in buffer

Require same uid as owner to unlink, not write permission

Do not fail due to file permissions on creation

Matches Posix.

Make fcntl not clobber access mode

Follow symlinks on O_STAT, unless O_NOFOLLOW is passed

Support unlink() on symlink

Symlinks in fuse

Return EINVAL for O_SYMLINK on non-symlink

[WIP] Symlinks

Allow seek beyond end of file.

This is enough to fix as. I don't know if it correctly fills the space
with zeros when writing beyond the current EOF.

Use ? instead of try!

I didn't notice there were two copies of this code