use non-gui matplotlib backend

Author: peitek

analysis/BehavioralBrain.py

@@ -1,6 +1,10 @@
 import numpy
 import pandas as pd
+import matplotlib
+matplotlib.use('Agg')
+
 import matplotlib.pyplot as plt
+
 import seaborn as sns
 import scipy
 

analysis/BehavioralSubjective.py

@@ -3,6 +3,9 @@
 
 import numpy
 import pandas as pd
+import matplotlib
+matplotlib.use('Agg')
+
 import matplotlib.pyplot as plt
 import seaborn as sns
 import scipy

analysis/BrainActivationAnalysis.py

@@ -1,3 +1,6 @@
+import matplotlib
+matplotlib.use('Agg')
+
 import matplotlib.pyplot as plt
 import numpy
 import pandas as pd