Added links to the SHA-3 wiki pages.
testing access
An example in second_example_queries was removed from `Tips.pm`.

The example 'root mean square 1,2,3' is for the plugin `Average.pm`.
Fixed a typo in the example query in Perimeter.pm.

Also, I added use utf8 in Xor.pm in hopes of fixing the 5 ⊕ 79 problem.
fix year-specific DateMath tests