Update Codeclimate instructions

Codeclimate has changed its api for SimpleCov
https://github.com/codeclimate/ruby-test-reporter/blob/master/CHANGELOG.md#v100-2016-11-03

See applied instructions at:
* https://docs.codeclimate.com/docs/travis-ci-ruby-test-coverage
* https://docs.codeclimate.com/docs/test-coverage-ruby

Author: abinoam

.travis.yml

@@ -44,3 +44,5 @@ install:
   - bundle exec rake install
 script:
   - bundle exec rake spec
+after_success:
+  - bundle exec codeclimate-test-reporter

spec/spec_helper.rb

@@ -3,10 +3,10 @@
 require 'digest'
 require 'chunky_png'
 require 'digest/md5'
-SimpleCov.add_filter 'vendor'
-SimpleCov.add_filter 'examples'
-SimpleCov.formatter = CodeClimate::TestReporter::Formatter
-SimpleCov.start CodeClimate::TestReporter.configuration.profile
+
+SimpleCov.start do
+  add_filter 'examples'
+end
 
 require 'gnuplotrb'