Fix incorrect advice and update syntax.

[crashoverride777]

This awesome guide needs some updates

1. Use swift 4 Syntax in readme
2. Protect from dynamism section is incorrect. Adding @objc dynamic is not needed for things such as scroll view delegates.
3. IBOutlets should always be forced unwrapped, like Xcode does by default, not optionals. Optional outlets is a debugging mess.
4. self should NOT be used unless required, as I mentioned in my other open issue. Stating self should be used at all times is categorically bad swift advice. This is no longer a matter of preference.
5. weak self should be handled with strongSelf (until swift 4.2) and not self. Self with single quotations is not supported.

Thanks again for this guide and the effort put in.