Update NEWS.html to vegan 2.2-0


git-svn-id: svn://svn.r-forge.r-project.org/svnroot/vegan@2907 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Merge branch 'master' into r-forge-svn-local

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/vegan@2908 edb9625f-4e0d-4859-8d74-9fd3b1da38cb