Disable rubocop

It causes more issues than it solves. Ideally we can switch to a
simpler formatting tool and make it part of commit hooks rather
than a CI step.

Gemfile

@@ -9,7 +9,6 @@ group :development do
   gem 'simplecov'
   gem 'samus', '~> 3.0.8', :require => false
   gem 'coveralls', :require => false
-  gem 'rubocop', '0.44.1', :require => false
 end
 
 group :asciidoc do

Rakefile

@@ -23,17 +23,12 @@ rescue LoadError
   nil # noop
 end
 
-desc "Check code style with Rubocop"
-task :rubocop do
-  sh "rubocop"
-end
-
 desc "Generate documentation for Yard, and fail if there are any warnings"
 task :test_doc do
   sh "ruby bin/yard --fail-on-warning #{"--no-progress" if ENV["CI"]}"
 end
 
-task :default => [:rubocop, :spec, :test_doc]
+task :default => [:spec, :test_doc]
 
 YARD::Rake::YardocTask.new do |t|
   t.options += ['--title', "YARD #{YARD::VERSION} Documentation"]