Allow parameters to be passed to Doctrine_Query::select()

While I believe it's not so extraordinary to have parameters in a SELECT clause, Doctrine_Query::select() does not allow to pass parameters, next to the SELECT clause. You can still pass any parameters to execute(), but I do believe it would be nice to be able to pass the parameter values right away to select() as you can with where() etc.

Example:

Doctrine_Query::create()>select('f.*, (f.id = ?) AS selected'))>from('Foo f')->execute(array($selected_id));

This principle would apply to any select-field that has a calculated value that comes from a parameter.