[dev] [st] bold as bright (again)

Some time ago, i submitted a patch that makes colors bright for bold
text. Most Terminals do that, and some programs rely on this (like
htop). The patch was rejected unless more people ask for it.

As it seems, i'm still the only one, but i modified the patch to make
the bold-is-bright behavior optional. Now i try again.

I attached two variants of the patch, one uses preprocessor directives
(pp.diff), the other not. Maybe i'm more lucky this time :)

greetings
stefan