Add info about new Auth events.

Refs cakephp/cakephp#5097
Fix typo in method name.
Document direct task execution subcommand necessity

In order to be able to execute a task via its parent shell, a sub command must be added to the Shell's option parser.
Merge pull request #1966 from robertscherer/patch-1

Document direct task execution subcommand necessity
Fix wrong method name

isWithinPast should be wasWithinLast
Merge pull request #1968 from berrygoudswaard/patch-1

Fix wrong method name
Merge pull request #1962 from cakephp/3.0-auth-events

Add info about new Auth events.