Use wait2 to get exit status
Reset block name after test

Avoid incorrect test name display on next failure.
Merge pull request #15 from xymbol/use-wait2

Use wait2 to get exit status
Merge pull request #14 from xymbol/reset-test-name

Reset block name after test
Run tests by scope name

```ruby
scope do
  test do
    raise "This is not raised"
  end
end

scope "scope" do
  raise "This is raised"
end
```

```
$ cutest -s scope test.rb
=> This is raised
```