remove lib/bio.rb to avoid conflicts with BioRuby
remove lib/bio.rb to avoid conflicts with BioRuby

BioRuby sets up autolod definitions in lib/bio.rb for various core
modules. bio-nexml carried over lib/bio.rb from the early development
days when it was supposed to be a core part of BioRuby. Now, whichever
appears first in the load path, bioruby or bio-nexml, gets loaded on
require 'bio'. This can cause weird problems.

nexml/bio-nexml