Panic when SSND chunk's offset and blocksize are non-zero

[AkiyukiOkayasu]

#33 (comment)

it doesn't seem to support offset and blocksize in the SSND chunk (those fields are rarely used so probably ok)

In most cases, this will not be a problem, but it should be handled appropriately.

pacmog/src/lib.rs

Lines 108 to 109 in cf65111

	assert_eq!(ssnd_block_info.offset, 0); //offsetとblock_sizeはほとんどの場合で0固定。したがって0で指定されたファイルにのみ対応する。
	assert_eq!(ssnd_block_info.block_size, 0);

[AkiyukiOkayasu]

Resolved in #52 .
But only not panic. offset and block_size of 0 are only supported.
This is because most AIFF files are typically 0 and there is little need to support them.