Trac 15061: use Sylvester matrix for resultants of multivariate
polynomials over base rings without conversion to Singular
fix magma(P) for P a multivariate polynomial ring
fix various Magma doctest failures
Trac 15061: delete an irrelevant doctest
16281: rewrite projective planes (as 2-designs)
trac #16269: Merged with #16280
remove deprecated code from #11033
remove deprecated code from #8930
remove deprecated code from #13211
remove deprecated code from #12587
remove deprecated code from #7371 and #10334
remove deprecated code from coxeter_groups
16281: reviewer's comment 1

- modify DesarguesianProjectivePlane in
  DesarguesianProjectivePlaneDesign
- remove ProjectivePlaneDesign
trac #16277: Yet another construction
trac #16281: Simplification
trac #16237: Indexing in IncidenceStructureFromMatrix method fixed. minor clean-up of Hadamard matrices; they are now normalised.
16281: long comment for the construction of the projective plane
trac #16281: correct a doctest
Add bridges and spanning trees functions for graphs
Merge branch 'develop' into public/ticket/10963-doc-distributive