Cast number to int or float explicitly

[HenryQuan]

In Python, this is not a big problem. However, this is causing some minor issues in Dart because int isn't double and visa versa. Now, num type is used when the number can be both int and double. However, I am not sure if this is a good practise.

We should discuss on where we should do the casting, Python or Dart. We can simply call toDouble() to make int a double in Dart. Alternatively, we can do it from Python in generate.py.

Also, this might not be a real problem at all.

[HenryQuan]

This has causing serveral crashes. We cannot possibly test all ships so we should always cast the number to int or double from the python side. This needs to be done soon.