Update Scrutinizer settings

This commit also fix some new recognized failures.
Merge pull request #5 from henriquemoody/scrutinizer

Update Scrutinizer settings
Create documentation on README.md file
Jared's editing suggestions for README.md
Merge pull request #6 from henriquemoody/documentation

Create documentation
Remove API.md file
Update package description on composer.json file
Create method `getPid()` on Pidfile class
Merge pull request #7 from henriquemoody/pidfile

Create method `getPid()` on Pidfile class
Move signal handlers to another namespace

Move to `Arara\Process\Handler` namespace.
Create SIGALRM class handler
Create PHP error handler class
Merge pull request #8 from henriquemoody/handlers

Centralize handlers for signals and PHP errors
Use an object as context instead of an array
Use context when executing action
Merge pull request #9 from henriquemoody/context

Use an object as context instead of an array
Allow more than one handler for the same signal
Merge pull request #10 from henriquemoody/handlers

Allow more than one handler for the same signal
Callback action class improvements

- Create method `getHandlers()` to return all defined handlers
- In order to make Callback action reusable all properties was changed
  to `protected`
Improve Child and Action events

- Create INIT event
- Create FORK event
- Remove sleep from Child class after fork
- Unset PID after SIGTERM or SIGKILL