Implemented from-the-end indexing in ranges using the a[..<1] syntax. Added `[..]. Still to do: Avoid fallback to `[] for ranges if it doesn't take two args. Rev: src/docode.c:1.181 Rev: src/interpret.c:1.358 Rev: src/interpret_functions.h:1.176 Rev: src/language.yacc:1.347 Rev: src/las.c:1.351 Rev: src/lexer.h:1.51 Rev: src/opcodes.h:1.41 Rev: src/operators.c:1.198 Rev: src/operators.h:1.16 Rev: src/pike_types.c:1.238 Rev: src/program.c:1.573 Rev: src/program.h:1.213 Rev: src/testsuite.in:1.741 Rev: src/treeopt.in:1.74