Package 'pracma' fzero() based on brent_dekker().

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/optimist@341 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Package 'pracma' 1.6.2 small correction.

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/optimist@342 edb9625f-4e0d-4859-8d74-9fd3b1da38cb