Add GenericName

I like the idea of "Bomns" being a class of applications you could
install (like "Web Browser"), 3omns being the specific implementation
(like "Firefox").

Plus apparently this fixes a build warning on OpenSUSE.
Don't install NEWS or README

Packages can optionally include them if they want, but it seems odd to
have make install drop just NEWS and README in the install dir.
Delay SDL_INIT_VIDEO, so b3_init works from tests