improve undo for text

Migrated from: https://bugs.launchpad.net/inkscape/+bug/1334310

Currently, undoing the typing of text does it one space or character at a time. That really is a bit ridiculous, in practice. Maybe text should be undone by everything that was typed in the last string of typing? So maybe a 2 second pause would mark the boundary of what gets un-typed?

Or maybe the typing of text should not be in Undo or Undo History at all? Maybe it should be undone via highlight/delete?

I'm not sure what the best solution would be. But I think there's some room for improvement, currently. Maybe this Issue can allow for discussion.

Thanks for listening.