Use space as default fillChar

Author: Vic-Nas

vicutils/printBin.py

@@ -2,7 +2,7 @@
 
 # Default configuration constants
 DEFAULT_UNIT_SIZE = 3
-DEFAULT_VALUE_FILL_CHAR = "_"  # Character used to pad node values (e.g., "_5_")
+DEFAULT_VALUE_FILL_CHAR = " "  # Character used to pad node values (e.g., "_5_")
 DEFAULT_CONNECTOR_FILL_CHAR = "_"  # Character used to fill horizontal gaps between node pairs