[Urwid] Optimize urwid - cutable benchmarks

[Ian Ward]

Rebecca Breu wrote:
>> Here are my bench_1 results (different computer this time):
>> 0.9.7.1:
>>    Minimum: 9.588382
>>
>> 0.9.7.1 with cutable:
>>    Minimum: 7.828077
>>    ~ 22% improvement
>>
> 
> Mmh, wouldn't one calculate:
> 
> (new_value - old_value) / old_value
> 
> Then you get about 18% improvement in this case...

Yep, it's an 18% reduction in time, which is 22% "faster". :-)

speed1 = d/t1, speed2 = d/t2, relative speed = speed2/speed1

.. or is measuring relative speed something only marketing folks do?