Merge 159 and 162

In this PR I will merge the PR #159 and #162 and try to add signature to logout request and response
@pitbulk could you paste the errors here? In travis I only see:
```
An error occurred while installing debugger (1.6.8), and Bundler cannot
continue.
Make sure that `gem install debugger -v '1.6.8'` succeeds before bundling.
The command "eval bundle install --jobs=3 --retry=3" failed. Retrying, 2 of 3.
```