Resolve "Problems with background I/O"

Closes #440 (closed)

src/virtmat/language/interpreter/session_manager.py

@@ -110,7 +110,9 @@ def get_prettytable(dataframe):
     table = class_(list(dataframe.columns))
     for tpl in dataframe.itertuples(index=False, name=None):
         table.add_row(tpl)
-    return str(table)
+    table.align = 'l'
+    table.max_width = 120
+    return table
 
 
 class SessionManager(InteractiveConsole):