growth factor update

[bodiyang]

As noticed from the recent CBO update work, the growth factors file has to be rechecked for factors which remain unchanged for the new years

When extending to a new year, the factors (ABENMCARE, ABENVET) which do not have new value change will be left as blank (or na). They would then be taken as 0 by the model, and this will lead to incorrect projections. The default value should be 1.

I have to manually correct these value each time after the update. Will try to build an automatic check in the update script.