Adapt tests to revs 2448, 2449

R-to-be-3.0.0 changes something in random number generation so that
all permutation-based tests will change. This update was made on
R 2.15.2.


git-svn-id: svn+ssh://svn.r-forge.r-project.org/svnroot/vegan/pkg/vegan@2450 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
resurrect weights for specaccum that were removed in r1606 on Thu, 26 May 2011

git-svn-id: svn+ssh://svn.r-forge.r-project.org/svnroot/vegan/pkg/vegan@2451 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Merge branch 'r-forge-svn-local'