[xmonad] patch: ShowWName flash window fixes

[wagnerdm at seas.upenn.edu]

> Yes, Increasing the visibility of the flash was my primary target here. The
> patch results in relatively more significant amount of padding in case of
> smaller sized tags.

>> If the idea is to make sure the window has a reasonable size, it makes
>> sense to pad it larger for smaller internal text because it doesn't need
>> (any/as much) padding if the text already forces it to have a reasonable
>> size.  ("Reasonable" defined as "easily visible")

Okay, pushed.
~d