[Helper] Automatically link to routes in site_url(), redirect() and anchor()

[eluser]zentair[/eluser]
Sure thing, though I am new to GitHub so please tell me if I did something wrong: https://github.com/philsturgeon/codeigni...or/pull/36

I've been thinking about not being able to match expressions in routes without parentheses and apart from being completely unable to think of an example where that would be useful its also kind of strange. For example:

Code:

// with a route
$route['product/:num'] = "catalog/product_lookup";

// What should $url be?
$url = site_url('catalog/product_lookup);

There are an infinite number of 'right' awnsers for what $url could be.