Search enhancements / highlighting

[GoogleCodeExporter]

It would be nice if TW will be able to highlight search results right
inside the document as Gedit.

Also I think that Find / Find next needs to be more intelligent. E.g. when
there's more matches Find automatically finds next, such as in Gedit / Kile
/ other editors. 

Finally, it's nice to re-bind Find next to F3, such as in Kile, Firefox
etc., possible as an alternative to CTRL+G.

Original issue reported on code.google.com by yury.v.zaytsev on 23 Mar 2010 at 12:39