tc ([cctype]) calling conventions listing and manipulations

• tc List all loaded structs
• tc [cctype] Show convention rules for this type
• tc=([cctype]) Select (or show) default calling convention
• tc-[cctype] TODO: remove given calling convention
• tc+[cctype] ... TODO: define new calling convention
• tcl List all the calling conventions
• tcr Register telescoping using the calling conventions order
• tcj json output (TODO)
• tc? show this help