Option for fixed-width UI

[petered]

Current display for experiment UI looks bad on terminal due to line wraps. Should have option for limiting width of display

[petered]

A bit tricky. PrettyTable allows multi-line cells in tables. I make a fork of the PTable to work on this. (we needed to modify their column-width-assignment code). The problem is we really need a nested table in the ui, of Experiment>Records. For now we do this by hacking the output of tablulate, but this becomes tricky when we have multi-line tables. So it remains on the TODO list.