Request for review: Grepview plugin rewrite

[Syron]

  > Can you open a merge request? will make it easier to review.

Well... I had a request opened, but a user commented with serious 
problems on that request, so I removed it. It turned out that a) his 
problems came from the "old" plugin, and b) there are/were still small 
bugs that are/were release stoppers (i.e. the blocking UI, and I still 
figured not out why IStatus does not work).

-- Syron