Clip to min and max range of input image, add missing clip parameter to ...

...other functions
Certainly! =)

```python
if mode == 'constant' and not (min_val <= cval <= max_val):
    cval_mask = (output_image == cval)
    output_image = np.clip(output_image, min_val, max_val, out=output_image)
    output_image[cval_mask] = cval
else:
    output_image = np.clip(output_image, min_val, max_val, out=output_image)
return output_image
```
This allocates at most 2 arrays and at best 1, while, currently, it's at most 3 and at best 2.