put sharing of logicals back into variant AND/OR returns
debug/tuning output/options in memory.c used in connection with sharing
use shared constants in parser
define 1-element pairlist constants, and use in parser
check that constant is not object, has no attr, has levels of 0, to protect against future expansion of constants
Have ReadItem pay attention to SharedList1 constants
tweak PRINT_TYPE_STATS output
update documentation on serialization