Added object classes, modified description, added FIXME to the code.

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/eventstudies@186 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Little modification in the text.

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/eventstudies@187 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Added classes to arguments, modified some text.

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/eventstudies@188 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Changed formatting

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/eventstudies@189 edb9625f-4e0d-4859-8d74-9fd3b1da38cb