Bunch of miscellaneous updates

I've dropped the ball on making smaller commits so now here's a big one

- Update sig for post-6.40 exes
- Some packet handlers have switches for packet sizes. Added a heuristic
  to capture this information
- Consolidated vtable alignment warnings
- Added script to debug similarity matrix

debug_similarity_matrix.py

@@ -0,0 +1,43 @@
+import click
+from vtable_alignment import Similarity
+
+from utils import HexIntParamType
+
+
+@click.command()
+@click.argument(
+    "similarity_json_file",
+    type=click.Path(exists=True, dir_okay=False, resolve_path=True),
+)
+@click.argument("opcode", type=HexIntParamType())
+def debug_similarity_matrix(similarity_json_file, opcode):
+    """
+    Given an old opcode, debug prints a row of the similarity matrix generated
+    from generate_similarity_matrix.py.
+
+    Example:
+    python debug_similarity_matrix.py similarity.json 0x200
+    """
+
+    entries = dict()
+    similarity = Similarity(similarity_json_file)
+    for new_opcode in similarity.new_opcodes:
+        entries[new_opcode] = similarity.lookup(opcode, new_opcode)
+
+    max_opcode = 0
+    max_score = -9999
+
+    print(f"Similarities for {hex(opcode)}")
+
+    for new_opcode, similarity in entries.items():
+        print(f"\t{hex(new_opcode)} => {similarity}")
+        if similarity > max_score:
+            max_opcode = new_opcode
+            max_score = similarity
+
+    print("Best match")
+    print(f"{hex(max_opcode)} => {max_score}")
+
+
+if __name__ == "__main__":
+    debug_similarity_matrix()