Matrices of Time series

• addts2tsmat — adds a ts to a tsmat
• db2tsmat — Converts a database into a tsmat
• ts2tsmat — Converts time series into a tsmat
• tsmat2ts — Converts a tsmat into time series
• tsmat_extrap — exatrpolates series in a tsmat
• tsmat_names — Changes how the names of a tsmat are modified after an operation