Update features.py

Fixed:
ValueError: Samples can not be a single string. The input must be an iterable over iterables of strings.

By:
entry_name_hashed = FeatureHasher(50, input_type="string").transform([raw_obj['entry']]).toarray()[0] 
with:
entry_name_hashed = FeatureHasher(50, input_type="string").transform([ [raw_obj['entry']] ]).toarray()[0] 

at line 192.

In this way an iterable over iterable over raw features is obtained, as transform() method require.

ember/features.py

@@ -189,7 +189,7 @@ def process_raw_features(self, raw_obj):
         section_entropy_hashed = FeatureHasher(50, input_type="pair").transform([section_entropy]).toarray()[0]
         section_vsize = [(s['name'], s['vsize']) for s in sections]
         section_vsize_hashed = FeatureHasher(50, input_type="pair").transform([section_vsize]).toarray()[0]
-        entry_name_hashed = FeatureHasher(50, input_type="string").transform([raw_obj['entry']]).toarray()[0]
+        entry_name_hashed = FeatureHasher(50, input_type="string").transform([ [raw_obj['entry']] ]).toarray()[0] 
         characteristics = [p for s in sections for p in s['props'] if s['name'] == raw_obj['entry']]
         characteristics_hashed = FeatureHasher(50, input_type="string").transform([characteristics]).toarray()[0]