Gk browser better data generator

Test data generator now much more flexible

Moved some column sizing stuff (should have been a separate PR, sorry)

Some clean up

@jpsim @alazier @tgoyne 
I suppose it depends on warning settings, but I do get a warning: 

https://www.dropbox.com/s/ttxo64eb2peb3r9/Screenshot%202014-09-02%2020.01.31.png?dl=0