Add check that out != "plotter_lib_pngs/"

plotter/Args.py

+import sys
+
 class Args:
     def __init__(self, filename, func, var=[None], mval=[None], oname=[None], out=[None], ndim = None):
+        if out == "plotter_lib_pngs/":
+            print("Output directory name can't be equal to " + out)
+            sys.exit(-1)
+    
         self.filename = filename
         self.var = var
         self.mval = mval