SVN url helper : current_url function added

[eluser]xwero[/eluser]
request_uri doesn't return the full url, script_uri does. most of the times request_uri is the same as php_self. And php_self got some bad press.

If you look at the form_open function of the form helper it adds a full url to the action too. I don't use the form_open function so i want a function that gets the full url instead of doing site_url('seg/ment/s'), current_url is born.