(bug 34977) Change Spanish formatnum behavior

Use non-breaking spaces as thousands separator.
Used the same $separatorTransformTable as in fr, it etc.
The format is the correct one according to official
standards and it's also currently in use "in the wild",
e.g. on Spanish Wikipedia, according to guidelines.

Change-Id: I1c9dfe1f02d907183fb671b7382f2eb706e57bab