Added Http timeout

[skiyo]

Useage:
HttpRequest.TIMEOUT_CONNECT = 1000;
HttpRequest.TIMEOUT_READ = 1000;
HttpRequest request = HttpRequest.post(url);
System.out.println(request.ok());

[kevinsawicki]

There are already methods to set this on a per connection basis (connectTimeout and readTimeout), I'd prefer not to make this global state driven.