Fix race and BMI.

* add fuzzy match for caucasians
* make BMI miscalculations return NA
Post-process smoking status.
Post-process LVEF value and flag.
Post-process "time to event" and MI during follow-up.
Caucasiens, BMI, and LVEF.

* fix messpellings for caucasians
* fix logic bug for BMI calculation of 0 value
* Just set all missing LVEF values to 0 instead of NA
Caucasiens are still a problem.
Fix overzealous LVEF availability.