Parentheses around conditional, refs #91.
Add ruler for unnecessary interpolation, refs #91.
fix broken regex for indent close

The following code was reported despite being clean:

```
{
  a: 1
}.each do |k, v|
  puts k, v
end
```

This patch fixes the multi-line code path and removes the unneeded line
transition logic from IndentationManager.
Merge remote-tracking branch 'acrmp/unnecessary-string-interpolation'
Merge remote-tracking branch 'acrmp/conditional-parentheses'
Merge branch 'fix_indent_on_close'