Consider adding a --fit flag

[raldone01]

I used tiv in the past. I now wanted to optionally support viu.
In tiv -h -w are max height/max width. I think this is what most expect.

My use case:
I use tiv and viu in my fish_greeting function on all my linux machines (shell script).

Image using tiv:

Same image using viu:

I don't think changing the behaviour would be an issue for many users.
To avoid doing a breaking change I would suggest adding a --fit option that changes the behaviour to make -h and -w max measurements instead.
Alternatively you can also reconsider #55.

I also noticed that the colors are off in viu.