overloading for -> and [] implemented

Rev: src/docode.c:1.7
Rev: src/interpret.c:1.19
Rev: src/language.yacc:1.17
Rev: src/las.c:1.11
Rev: src/lex.c:1.10
Rev: src/object.c:1.8
Rev: src/peep.c:1.4
Rev: src/peep.in:1.2
Rev: src/program.c:1.12
Rev: src/program.h:1.6