fix impute wim

bunch of minor runtime fixes to get things working, like loading up
libraries, etc.
move amelia filename creation and pattern to utils

using it in wim impute as well as vds impute, and for searching, so
belongs in utils not in the vds impute code file
add in code from bdp

needed to add some more functions from bdp that were missing here.
get speed, recode/create variables, etc

modified:   lib/wim.loading.functions.R