removing support for some regular operators
changed to with clauses to provide better error information
fixes to preserve origins when unquoting
removing alternative productions from SDF3 grammar
marking sdf2 style productions as deprecated
allowing template productions inside context-free syntax section and removing angle brackets from kernel sorts
changing all deprecated template sections for context-free syntax
desugaring from square bracket templates to templates and to SingleLineTemplates
fixes to support templates inside context-free syntax sections
lifting sdf2 style constructor to sort.cons style
symbols inside placeholders
generated files in separate folders