Improved contextual toolbar positioning

[ncri]

Fixes the contextual toolbar to cover selections that are about to be edited.

In case there is a selection, move toolbar on top of it and align with
start of selection. Else move it on top of current position, center it and move
it slightly to the right.

Hope you like it!

In the future it would probably be best to also test for the case when the toolbar
will popup outside the visible area, like for text on the top of the client window,
and reposition it to a visible position.

A general question: I was building hallo.js with these changes before committing.
Shall I always do this or rather not check in new builds?

[bergie]

@ncri thanks, it is indeed less "on the way" like this. But still, I'd rather have it below the selection, not above

[ncri]

Would you be okay with adding an option for changing it to above (default below)? I'd like to avoid having to use my own fork. :)

[ncri]

And maybe others like above as well...

[bergie]

@ncri sure, why not. PRs welcome :-)

[ncri]

sure, ill do it ;-)

[ncri]

I could just add to this one if you reopen it, maybe good to keep the reasoning