Add argument names to rint and first use with pbinom

[jeremyirilli]

As you can see, this new feature does not break the previous functionality of not using argument names (I only added some tests without changing the rest)

?- interval(pbinom(10...12, 20...21, 0.6...0.7), Res).
Res = 0.026389940701283972...0.5841070624424646.

?- interval(pbinom(10...12, 20...21, 0.6...0.7, true, false), Res).
Res = 0.026389940701283972...0.5841070624424646.

?- interval(pbinom(q=10...12, size=20...21, prob= 0.6...0.7, true, false), Res).
Res = 0.026389940701283972...0.5841070624424646.

?- interval(pbinom(prob=0.6...0.7, q=10...12, size=20...21, true, false), Res).
Res = 0.026389940701283972...0.5841070624424646.

?- interval(pbinom(prob=0.6...0.7, q=10...12, size=20...21), Res).
Res = 0.026389940701283972...0.5841070624424646.

?- interval(pbinom('lower.tail'=true, prob=0.6...0.7, q=10...12, size=20...21), Res).
Res = 0.026389940701283972...0.5841070624424646.

?- interval(pbinom('lower.tail'=true, prob=0.6...0.7, 'log.p'=false, q=10...12, size=20...21), Res).
Res = 0.026389940701283972...0.5841070624424646.