New wrapper for Singular triangular decompositions

[YueRen]

And sorry for the unnecessary deletion of a trailing whitespace in docs/src/CommutativeAlgebra/ideals.md, my editor is overzealous at times.

[thofma]

Minor nitpick: I think we don't capitalize anything, not even names. So the algorithm symbols should also all be lowercase (and snakecase). (For example, the option for groebner bases is called algorithm = :buchberger).

So I guess it would be :lazard, :lazard_factorized etc

[YueRen]

Minor nitpick: I think we don't capitalize anything, not even names. So the algorithm symbols should also all be lowercase (and snakecase). (For example, the option for groebner bases is called algorithm = :buchberger).

So I guess it would be :lazard, :lazard_factorized etc

No problem, that was an easy change.

[afkafkafk13]

Looks fine. Thank you for doing this.

Just as a sideremark: the doctests do not completely test the example, as some of the results are not spelled out due to size. But I do not see this as a problem for this particular code, as it is only wrapping a (stable) Singular-library command.

[YueRen]

@afkafkafk13 I have added the option to specify the ordering of the variables for the triangular decomposition (which I need for my tropical code) through a keyword argument ord (similar as in groebner_basis). The triangular set starts with a univariate polynomial in ord[1], a bivariate polynomial in ord[1] and ord[2], etc. The default is the same as in Singular (ord[1] is the last variable, ord[2] is the second-last variable, etc).

[afkafkafk13]

@YueRen : Resolving the conflict in the bib-file seems to have messed up the file, but I do not see what goes wrong. (Everything was fine with your addition, master was fine with the addition of Lan71, but now bibtool complains)

[YueRen]

The bibliography should be fixed now, just a problem with the ordering of the bib entries.