maze.js : Added [height] [size] and [flags]

It still works as usual with only this : */maze.js 1*

I've added an argument for the height of the walls, one for the size of the maze, and also some "flags".

**Example :** */maze.js 1 5 5 3 3 ifceav*

    - 1 : stone walls
    - 5 cells in width
    - 5 cells in length
    - 3 : walls of three blocks height
    - 3 : walls spaced by three blocks

**Flags :**

    - i : adds an entry and an exit
    - f : adds a floor
    - c : adds a ceiling
    - e : places air blocks (usefull to clear what would be inside the maze)
    - a : places air blocks only (walls, floor and ceiling will be ignored)
    - v : creates a vertical maze

If you want to add some flags, don't forget to type the values for height and size :

- This will not work : */maze.js 1 5 5 if*
- This will work : */maze.js 1 5 5 2 1 if*