include ddir in csv dumps
remove Histogram() function
fix bug in interaction between numjobs/numfiles

*sigh*
remove unused Map/Reduce/Filter

fun to write, but not worth the complexity
add stats sumarization, refactor things as needed

New LatRecs.Summarize() function calculates a bunch of rollup info
from the full-resolution data.

WriteFiles() will write that data to a JSON file + CSV files for
the summarized time-series data.

Changed LatRecs to be []*LatRec and updated code as necessary.
This should save a little memory.