Common prefixes of column headers in the web app should be elided

```
The column headers in the web app are too long and make the data difficult to
see on smaller screens.

For example, i had a benchmark with two parameters "capacity" and "queueType",
but in the web ui they display as
SCENARIO.BENCHMARKSPEC.PARAMETERS.CAPACITY and
SCENARIO.BENCHMARKSPEC.PARAMETERS.QUEUETYPE

which ends up making the columns much wider than they need to be and pushes the
importand data off to the right of my window so to read my results i need to do
a lot of horizontal scrolling.

I think if all the column names have the same prefix the prefix could be
dropped. For my purposes "capacity" and "queuetype" would be sufficient.

```

Original issue reported on code.google.com by `lu...@google.com` on 6 May 2013 at 6:25