Adding rspec tests.
Remove Gemfile lock from git, stylize Gemfile

Move spec to separate file from class

now we can use either `bundle exec rake` either
`bundle exec rspec <path to specfile>`. First variant
will test whole repo. Second - just one file or if you will
provide pattern - you will get file matching tested.

Lock rubocop version for now, as new version of it produces a lot of new offence reports

Ruby 2.1 for travis testing

Fix issues with travis and ruby 2.1

remove unused variable from mysql check

Add rspec to travis run

Try to run rspec via rake

Update Readme with RSpec testing details

Fix typo in README

Remove unneeded lines
Merge pull request #431 from kalabiyau/rspec_coverage

Rspec coverage added as an option for testing checks