Depend on quantmod >= 0.4-3 and use importDefaults from there instead of the deprecated Defaults package

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/blotter/pkg/FinancialInstrument@1660 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
update NEWS only

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/blotter/pkg/FinancialInstrument@1661 edb9625f-4e0d-4859-8d74-9fd3b1da38cb