Update Travis settings for Rubinius

/cc @brixen
only warn if entities are not included

currently it warns when they are blank, too.
Merge pull request #532 from matthewrudy/no-warning-on-empty-entities

only warn if entities are not included
Prepare for version 5.7.1 release
Remove pry-rescue from Gemfile
Move LineLength next to MethodLength
Limit class length to 85 lines
Alias Twitter::Tweet#reply? to Twitter::Tweet#in_reply_to_user_id?

Before this patch, manual replies (created without pressing a reply
button) would return false, since they do not have an
in_reply_to_status_id.
Don't iterate over modules
Use RSpec 3 comptaible syntax
Use resolution-independent SVG badges [ci skip]