Added construct.indicator

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/btutils@11 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Added documentation

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/btutils@12 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Added licensing

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/btutils@13 edb9625f-4e0d-4859-8d74-9fd3b1da38cb