The maze and the numeric line views are not well defined

[lgraziani2712]

Right now, both have hardcoded positions, and a simple change of structure results in a visually wrong game.

Things need to be done

• To the numeric line:
  • Make margins constants. It doesn't cares how many numbers has.
  • Move its pivot attr to center-top.
• To the maze:
  • Add margins to blocks. Margins have to be constants and equal to the numeric line ones.
• Integrate and test them with multiple game configurations.