Great, thank you for the information @jairideout and @colinbrislawn ! I'll look out for the 2018 release.
Can I ask one more question? For the graph below, there are 0, 1, and empty cell/blank values in the metadata file (for n=53 samples).
However, as you can see below, only ~seven 1's show up on the graph, and the remaining forty-five values are all seen as missing, despite there being ten empty cells, thirty-three 1s, and ten 0s. Shouldn't all the values, including the blanks despite not being 'missing' per se, be graphed together (respectively)? just wondering how to get around this...
Since empty cells are not being seen as "missing data", currently, what are the ways missing data can be seen for the time being? 
Would it be a good idea to replace all empty/missing data cells with "NA" for the time being (as NA is not a real metadata value in my dataset)?
side note - in the next release, could missing data be indicated by empty cells, as well as periods (".") like how missing data are generally handled in SAS? I realize SAS may not be as commonly used in this area, but just putting it out there... 