Producing a (larger) t-dist table for two-sided region testing; extended approach, related to #148

[GerHobbelt]

Producing a (larger) t-dist table for two-sided region testing, using the table data published in the t-dist wikipedia page: https://en.wikipedia.org/wiki/Student%27s_t-distribution. See also 'Analysis' comment at issue #148.

Note that this commit can be tweaked when anyone desires:

• change the if (0) ... code at the end of the diff to if (1) ... to get a dump to console of the generated t-dist table (up to n=120 degrees of freedom, rather than just 30)
• change the var j = 5; to another column index, e.g. j = 7 for p=0.01 (~ 99% confidence) when you want to calculate figures using a different p assumption.

This commit also adds a few more URLs to reference pages for other bits of the statistics calculus' math background related to the issue/analysis in #148.

[Uzlopak]

I will adapt this to my fork