Perspective matrix for Vulkan

I'm using nalgebra-glm to do some work with the Vulkan API through Vulkano. The perspective matrix generated by `perspective_rh_zo` flips the Z axis in the wrong direction. I chose this function since Vulkan operates with a right handed coordinate system and the Z axis goes from 0 to 1 rather than -1 to 1.

According to these two posts:
[Why projection matrices typically used with OpenGL fail with Vulkan](https://johannesugb.github.io/gpu-programming/why-do-opengl-proj-matrices-fail-in-vulkan/)
[Setting Up a Proper Projection Matrix for Vulkan](https://johannesugb.github.io/gpu-programming/setting-up-a-proper-vulkan-projection-matrix/)

Following the math from the second post shows all that needs to change to create a 'proper' Vulkan perspective matrix is change:
```rust
//matrix_clip_space.rs
//pub fn perspective_rh_zo
mat[(0, 0)] = one / (aspect * tan_half_fovy);
```
to
```rust
mat[(0, 0)] = aspect / tan_half_fovy;
```

I'm not sure if a new function should be added or if the existing one should be changed.