- replaced 'sn' dependency with 'gamlss' for skew-t fit


git-svn-id: svn://svn.r-forge.r-project.org/svnroot/returnanalytics@3308 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
- switched dependency from 'sn' to 'gamlss'


git-svn-id: svn://svn.r-forge.r-project.org/svnroot/returnanalytics@3309 edb9625f-4e0d-4859-8d74-9fd3b1da38cb