Replace varargs[Value] with varargs[Value, toPreserves]
Allow exceptions in fromPreserves
Cannot restrict effects here because hooks would be silently
rejected for posssibly raising exceptions.
encoding: integer encoding fix
Escape symbols with ascii space 0x20
Remove stale E generic parameters
toPreserves: embed any EmbeddedRef value
decoding: detect set and dictionary duplicates
Add string operator for seq[Value]
Convert seq[Value] to the expected Preserves text serialization.
initDictionary with capacity