Ability to replace or disable default scope on load

[roxblnfk]

#51

$select->load('comments', ['load' => new PublicCmments()])

Now it works so that the new Scope (Constraint) is added to a default global Scope.

It would be very cool to be able to replace or disable a default Scope

[wolfy-j]

See other tickets as well, we are going to use new parameter "scope" to replace currently active scope/constrain.

[roxblnfk]

Implemented in v2.0.0 (#200): the scope option of load() / with() now replaces the default scope instead of adding to it — ->load('comments', ['scope' => new PublicComments()]), and ['scope' => false] disables it. Keeping the override when Select is cloned was fixed in v2.17.0 (#569).