(resolve #10) Fixed buffer overflow, when the block was corrupted we were not returning.
Which made a read to a buffer, and given that block_size could be greater than the buffer size, it was overflowing :shame:
(resolve #8) Receipt now accepts an environment.
(resolve #7 and #5) Now the cache provides a fast way to check for block existance in memory. We also handle recovery from missing blocks in the file system ( two shots one commit )
Check for the offset being greater than the amount of blocks ( that is, the corrupted block is a parity ) to prevent pruning the blocks ( as they are not corrupted )