Extension to Hash to create URL encoded string from key-values
Returns string formatted for HTTP URL encoded name-value pairs. For example,
{:id => 'thomas_hardy'}.to_http_str # => "id=thomas_hardy" {:id => 23423, :since => Time.now}.to_http_str # => "since=Thu,%2021%20Jun%202007%2012:10:05%20-0500&id=23423"
[Validate]