Add spec for url_encode on date
user
```ruby
require 'spec_helper'

describe Twilio::Util do
  include Twilio::Util

  it 'should parse a Date object' do
    today = Time.now
    url = url_encode({'DateSent>' => today})

    url.should == "DateSent%3E=#{today.strftime('%Y-%m-%d')}"
  end
end
```
assistant