added vignette to ./inst/doc as it can not easily build by r-forge servers

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/c060@169 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
uploaded package vignette to downloads folder and liked it to main.html

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/c060@170 edb9625f-4e0d-4859-8d74-9fd3b1da38cb