trial mods to trigger_vds_plot

made it like trigger_vds_impute, except for the local search bit

should perhaps make that a parameter?

also I think I am searching for .txt files rather than .RData files

still haven't modded the vds_plots.R file
ready to test triggering vds plot

modified trigger_vdsplot to get just the RData files
created vds_plots.R, copied from bdp, edited to follow vds_impute.R