Column resizing should communicate new width to cell renderers

[uap-universe]

This fork introduced a new feature that allows resizing of columns cells.

The way this is achieve is to register a mouse event listener to the header cell and change the width of that cell (and it's sibling) according to the mouse offset when dragging the mouse.

However, the individual cell renders are not notified about the width change. This is problematic for cell renderers that use the width to constrain the contents (e.g. div containers that use text-overflow: ellipsis).

Currently, the cell renderers are usually tied to the width configured in the settings object, which should be the initial width of the column (which is also not always true, see #35 ).

There should be a reliable (and preferably cost efficient) way to communicate width changes to cell renderers.

[uap-universe]

I put this into the 2.9.0 milestone, because it looks achievable and 2.9.0 is quite empty, yet. But if it turns out to be way more complicated, it may also be thrown out of the milestone as fast as it came in.