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

Example : /maze.js 1 5 5 2 1 ifceav

1 for stone walls
5 cells in width
5 cells in length
2 for walls of two blocks height
1 for walls spaced by one block

i adds an entry and an exit
f adds a floor
c adds a ceiling
e places air blocks
a places air blocks only
v creates a vertical maze