Divide glm::vec3 by its own member

Hello,
I have come across a strange issue. If you type

```
glm::vec3 v(1, 2, 3);
v /= v.y;
```

then v will hold 
x = 0.5, y = 1, z = 3

instead of the expected

x = 0.5, y = 1, z = 1.5

This issue is present with all glm::vec types. 

Edit: I was just investigating it more, it seems to be the case with all arithmetic operators.
