[pumpio] Fixes/imports: (#661)

[pumpio] Fixes/imports: (#661)

* [pumpio] Fixes/imports:
- added curly braces and spaces for better readability
- merged 2 `if()` blocks into one for lesser nested code blocks
- added type-hint `App` and `array` where applyable
- better "import" (`use` under PHP) classes and not reference them directly,
  reducing and improving readability

* [pumpio] Fixes:
- x() is deprecated, let's use !empty() instead
- added spaces for better readability

* [pumpio] Fixes:
- added missing App "imports" (thanks to MrPetovan)
- added type-hint array for $b
- added some spaces