Adding functions and documentation for estimating volatility, covariance, and correlation

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/uwgarp@122 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
forgot man page for simpleVolatility

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/uwgarp@123 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Cleaning up vignettes folder

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/uwgarp@124 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Renaming RB vignette to a more descriptive name

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/uwgarp@125 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Deleting pointless file in vignettes folder

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/uwgarp@126 edb9625f-4e0d-4859-8d74-9fd3b1da38cb