rd2man-lib.rb needs option to specify a different section

[skittleys]

r2man-lib.rb hard-codes the man section as "1". This is acceptable as a default, but there should be an option to change it.

Original Debian bug report (from 2006): https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=380559

[uwabami]

Thanks for your report (and Sorry for missing these report).
Add these feature in next release.