Add slony1 formula

[allenhuang]

Add slony1 formula for homebrew

[adamv]

I renamed this to "slony" instead of "slony1", and took out the configure switch that wasn't recognized, see my push above.

But this can't install without Postgres, so you'll need to add a Requirement to handle that. Grep the existing formulae for Requirement and find the ones that make sure Postgres is installed. Note that we don't depends_on 'postgres' because the user can install PG outside of HB and we also want to support that.

[allenhuang]

OK! Thanks for the direction. I'll fix it and request it later.

[adamv]

Closing since this is a duplicate now.