Update phpdocs (static return types)

Also made the Closure return consisten use \Closure and some small typos
Merge pull request #1728 from barryvdh/4.0

Add static return types to phpdocs
Merge branch '4.0'
updated README.md with working code order & objects

Added `Dispatcher` and `Container` creation/passing to `setEventDispatcher` so the code can be used (`setCacheManager` example could benefit from the same treatment).

Also moved `bootEloquent` below the `setEventDispatcher` (and other) calls. If it's called in it's old location above `setEventDispatcher`, than `setEventDispatcher` fails.
Merge pull request #1768 from BigBlueHat/patch-2

updated README.md with working code order & objects