Request for 'mode=scale' Support

[nyan-left]

Hi,

I would like to suggest adding a mode=scale functionality to the library. This mode would provide scale handles as spheres at the tips of each axis translate arrow.

I'm willing to contribute to this feature with a pull request.

Please let me know if you're open to this idea :)

[nyan-left]

Realted: #36

[WREQI]

I also hope to have