object class for planar difference sets

Changes for 1.000 - 2023-07-08T06:15:12+02:00

• revised data structure
• added principal elements arithmetic
• introduced three types of reference sets
• added mapping sets to lambda and theta
• improved compression in database
• calculated reference sets for all samples
• consolidated and extended example scripts
• added handling of large sets
• added checks to avoid arithmetic overflow
• added class methods for space properties
• extended documentation
• removed deprecated check_elements method