Bug fixes for version 6_0_01

1) Bug in one of the performance optimizations.

Updates for version 6_0_01

1) Allow negative indexes by default

2) Allow indexes to be X or Z and replace the access with X as for

out-of-bound accesses.

6.0.01

6.0.00

5.0.24

5.0.23

5.0.22

5.0.21

5.0.20

5.0.19

5.0.18

5.0.17

5.0.16

5.0.15

5.0.14

5.0.13

5.0.12

5.0.11

5.0.10

5.0.09

5.0.08

5.0.07

5.0.06

5.0.05

5.0.04

5.0.03

5.0.02