refactor: code improvements without affecting logic, part 3.

[marcosmarcolin]

• Typed returns
• Micro-optimizations
• Update some phpdoc comment blocks
• Remove some unused or unexpected parameters
• Declare some attributes

As there are no unit tests yet, I tested it in a real application, and it didn't imply in the operation, everything ok.

I would like to test it in real life too.

[walkor]

Thanks