Substructure Name Selection (#42)

Since the argparse argument was already present without any use, I added
in logic to gather data based off of the users preference with the default
being 'OPT'. This is useful if you want to gather data from a particular
substructure that you are not parameterizing.

q2mm/calculate.py

@@ -189,12 +189,17 @@ def main(args):
     # If we remove/with sorting removed, the Datum class is less
     # useful. We may want to reduce this to a N x 3 matrix or
     # 3 vectors (labels, weights, values).
+    sub_names = ['OPT']
+    if opts.subnames:
+        sub_names = opts.subnames
     if opts.fake:
         data = collect_data_fake(
-            commands, inps, direc=opts.directory, invert=opts.invert)
+            commands, inps, direc=opts.directory, invert=opts.invert, 
+            sub_names=sub_names)
     else:
         data = collect_data(
-            commands, inps, direc=opts.directory, invert=opts.invert)
+            commands, inps, direc=opts.directory, invert=opts.invert, 
+            sub_names=sub_names)
     # Adds weights to the data points in the data list.
     if opts.weight:
         compare.import_weights(data)