Example:
var login = new Control("someLogin");
c.setErrors({"notUnique": true});
expect(c.valid).toEqual(false);
expect(c.errors).toEqual({"notUnique": true});
c.updateValue("newLogin");
expect(c.valid).toEqual(true);
BREAKING CHANGE:
Before:
ControlGroup.errors and ControlArray.errors returned a reduced value of their children controls' errors.
After:
ControlGroup.errors and ControlArray.errors return the errors of the group and array.
And ControlGroup.controlsErrors and ControlArray.controlsErrors return the reduce value of their children controls' errors.
Closes#4917