Ruby 1.9 regexp fix

The following warning is showing up in the ruby 1.9 tests a bunch:
``` 
/home/travis/build/Crabgrass/Crabgrass-Core/vendor/gems/riseuplabs-greencloth-0.1/lib/greencloth.rb:586:
  warning: nested repeat operator + and ? was replaced with '*'
```

I took a close look at the regexp in question. Looks like it can be simplified and the warning would be turned off. But I think the original intent was different from what the regexp does now. So checking back...