feat(module): Show available diagrams in corpus

Add a file crawler for *.png files in the `_report` method of the Corpus
class which adds the availalbe diagrams for specific contrasts.

itten/corpus.py

@@ -37,12 +37,15 @@ class Corpus(object):
             movie = m.name
             status[movie] = {}
 
+            # get info about movie file
             video = m / ('movie/' + movie + '.mkv')
             status[movie]['video'] = video if video.is_file() else None
 
+            # get info about frame images
             frames = len(list((m / 'frames/240p30/').glob('*')))
             status[movie]['frames'] = frames if frames > 0 else None
 
+            # get info about data pickles
             status[movie].setdefault('data', {})
             data_files = (m / ('data/')).glob('*.pkl')
             for d in data_files:
@@ -52,7 +55,15 @@ class Corpus(object):
                                                  d[-3], {}).update(
                                                  {d[-2]: True})
 
-            status[movie]['visual'] = 'NEEDS IMPLEMENTATION'
+            # get info about diagram *.png files
+            status[movie].setdefault('visuals', {})
+            vis_files = (m.glob('*.png'))
+            for v in vis_files:
+                v = v.name.split('_')
+                status[movie]['visuals'].setdefault(
+                                                    v[-4], {}).setdefault(
+                                                    v[-3], {}).update(
+                                                    {v[-2]: True})
 
         return status