Positions with incorrect type should raise a TypeError

[victorpoughon]

As of 0.7.0 this code runs without error, and the sketch is not moved but stays at 0, 0:

from build123d import *

sketch = Pos(0, "blip") * Circle(5)
sketch

We should add some type checking to raise a TypeError here. This can happens quite easily if the coordinate comes from another data type like numpy or such. It can pretty easily be wrapped into a np.array or something, then it's really confusing why no transform is applied.