All versions of Growth Charts UK-WHO

Faster and slicker interface. Lots of bug fixes and improvements. Major changes: - Added BMI centile calculator. - Added head circumference centiles > 2 years old. - Graphing is now plotted on a z-score scale (rather than probability), so that centile lines at the extremities are equally spaced out. - Now displays both z-scores and centiles for the research people out there. - Age is now also displayed in weeks until 1 year of age (to make it easier to plot on Red Book paper growth charts).