ar-vinyeard compiles and runs: - ar-function-kernel uses int for sign rather than bool in sign_at - switched to dealing with a single functions themselves in value_at - order of thresholds is handled correctly in ar-vineyard (max is the last one)

add_subdirectory			(alphashapes)
add_subdirectory			(ar-vineyard)
add_subdirectory			(cech-complex)
add_subdirectory			(grid)
add_subdirectory			(triangle)