The package enables the user to typeset Skyline logic puzzles
(aka Skycrapers, Wolkenkratzer, Hochhäuser, ...),
incl. Skyline Sudoku and Skyline Sudoku (N*N) variants. 

There are skyscrapers located in each cell. Try to find out
the height of the skyscraper in the respective cell. There are
heights of 1 to MAX in every row, every column, and in each of
the two diagonals if indicated. Some cells may be empty (parks).
The numbers around the grid indicate how many buildings you can
see from this position when you look at the skyscraper lineup.
Bear in mind that only those skyscrapers are visible which are
higher than the ones in front.
