Update to fix crypto text normalization.

This would update the readme for this exercise to be consistent with the source problem and to keep the idea of "square" more exact.  If this is changed, then the following change should be rejected:
exercism/xjavascript#61

If this is rejected, that change should be accepted.
I think the cipher text is correct and that various current example solutions are incorrect.  Compare with the the original problem description at the source referenced in the yml.  The description in the readme looks consistent with the source document.  This cipher text looks consistent with the descriptions and this is the cipher text given on the source page.  I think it is the code which doesn't match the specification.

The two spaces between the last word is also copied from the source page.  We could specify to put those extra spaces in, but I'd be in favor of taking them out of our readme.  I think we should also show this on a single line,

    imtgdvs fearwer mayoogo anouuio ntnnlvt wttddes aohghn sseoau