Update Swift syntax per Beta 5...

Add override and require to initializers.

IBOutlet properties default to weak.

Nil-checking optionals must be explicit. This also
means force-unwrapping some Bool checks.
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bridgeToObjectiveC no longer seems to be
available.

Update section comments due to fixed jump menu
symbol listing. This includes re-organization.

Some method signatures are updated per SDK
changes.

The += operator no longer appends to list.

Remove some extra parens around conditionals.