Modified Syntax data type to include ellipsis sym

Allow the data type to hold an arbitrary ellipsis identifier. The macro system still needs to be updated to make use of this identifier.
WIP adding ellipsis symbol parameter

Work in progress to add the ellipsis symbol parameter to all functions in the syntax-rules system.
WIP, code compiles but gets stuck during transform
Debug in progress
Added more debug code
More debugging
Fixed hang and removed debug code
Fixed formating
Updated 3.13 section
Added a TODO