Moves x2 and y work on megaminx but not other dodec puzzles like gigaminx and pentultimate

[rokicki]

To Reproduce Steps to reproduce the behavior:

1. Go to alpha.twizzle.net/explorer and choose gigaminx.
2. Type x2 or y in the algorithm box.
3. See red.

Expected behavior The algorithm box should not be red; the moves should be accepted, displayed, and animated.