[pdl-stats] ols and missing values

[Ingo S. <in...@gm...>]

Hi,

recently I've needed some simple pearson's correlations and found out
that ols can't handle missing values elegantly. fill_m doesn't do the
job if you need also p-values. So Ichanged ols to filter rows from y and
ivs that contain bad values, then clear the flag before continuing. This
is based ona flag.

Thing is, I've never used git so far,I managed to clone and pull, butam
unsure about how to commit GLM.pp and push it to the server for you to
review.

Thanks
Ingo