Add a search field

[perguth]

1. As a user I want to search through *the displayed* log file.
2. As a user I want to search through *all* log files.

We do 1, should we also do 2? @ThomasWaldmann

[ThomasWaldmann]

as search is a completely new feature, I delayed that to 0.3 milestone, so we can do a 0.2 release with all the smaller improvements.