skip Typhoeus cert test in non-SSL mode
stop tolerating Ruby 2.0 failures on Travis CI
fix file uploads with Ruby 2.0 net/http

Rewrite Faraday::CompositeReadIO because the one inherited from
multipart-post library doesn't behave well when used with
IO.copy_stream which net/http uses internally in Ruby 2.0.
include em-synchrony in Ruby 2.0
fix copy_stream test for Rubinius and JRuby
Merge branch 'ruby2-compat'