Fix radio() being called incorrectly by input().

Refs #3317
Fix radio widget not generating labels.

Labels should only not be generated when label=false.

Refs #3317
Add tests for non array versions of options.

Both radio() and select() need to accept Collection/Traversable objects.
Failing to do so makes FormHelper sad when an ORM\Query is passed in.

Refs #3317
Fix overzealous array cast in multiCheckbox.

Refs #3317
Merge pull request #3324 from cakephp/form-fixes

Fix FormHelper + ORM\Query integration