Organization

Was rather exhausted when I wrote some of this code. I did write tests for everything. Each commit is standalone.

For the last commit, which should maybe have a longer commit message, I fixed a bug where certain types of storage proofs were actually impossible. When creating merkle roots and verifying merkle proofs, the last segment of the file does not get padded out. Prior to this PR, when creating merkle proofs, the last segment of the file DID get padded out, which would result in invalid proofs being created. Invalid proofs would only be created if the segment that needed to be provided was the last segment (a rare occurrence) AND that segment was not the full 64 bytes.

This bug has been fixed. BuildMerkleProof now works correctly, and VerifyMerkleProof verifies the proofs correctly. This ends up being a softfork.