CRAN release 1.4.0

This is a major release with the inclusion of several new features.

• Smooth accelerated failure time models have now been implemented, including natural splines and time-dependent acceleration factors.
• Standardised estimators (e.g. survival, survival differences and attributable fractions) for unclustered and clustered data.
• Predictions for survival in the uncured.

There have also been several bug fixes.