* Renamed sha-2 and content-Type properties to sha2 and contentType for easier reference as properties
(many languages don't like - in property names)

* Added clarifying requirements
* Added requirement to include hash in each part's header, so receiver doesn't
have to guess which hash length to use when verifying

* Added an example
minor clarification:
"only send one copy" language only applies within a single message
Added flag to include/exclude attachments when retreiving statements
(trivial) updated example hash

Hash in the example was calculated improperly, updated with correct hash.
Merge pull request #87 from bscSCORM/binary

Attachment example, clarifications, minor changes