Adding new plantri spkg
Merge changes of #16972 into this branch
#16970: Adding method to generate plane graphs
#16970: Adding method to generate plane triangulations
#16970: Changed formation of command
#16970: Added method to generate quadrangulations
Trac #17021: Faster creation of words by the parent.
#16970: Renamed plane graphs to planar graphs
#16970: Removed duplicate references
#16970: Added new functions to documentation
#16970: Correct handling of case where order is equal to 1
#16970: Extended documentation
#16970: Extended documentation
#16970: Updated the description of the output
#16970: Replaced plane by planar
#16970: Extended documentation for triangulations
#16970: Correct handling of order that is too small for plantri (triangulations)
#16970: Correct handling of order that is too small for plantri (planar graphs)
#16970: Correct handling of order that is too small for plantri (quadrangulations)
#16970: Extended documentation for quadrangulations