Better presentation of multiblock saves

Beyond the first block, no block data is displayed - the blocks
are apparently just a storage area at this point
Removal of example animecheck optparse code
Removal of shift_jis2unicode - not needed
Removal of trailing null bytes on gamePlayThroughIdentifier
Cleanup
Fix exception format string
Permitting corruption with multiblock saves

I have a few examples of multiblock saves where the middle/end
blocks have a bad XOR, yet work on the PS2. I've therefore
downgraded the exception to a warning.

A warning has also been added for unusable blocks