Clarify JSON Procedure with Requirements

Follows @fugu13 's suggestion https://github.com/adlnet/xAPI-Spec/issues/419#issuecomment-25571845
Add optional/required for a number of tables
fixed mbox related links
lower case "object" per https://github.com/adlnet/xAPI-Spec/pull/422#issuecomment-25652244
Endpoint in example incorrectly included / on the end as well as capital S

Fixed to /statements instead of /Statements/
7.7 Correct capitalization of property in /about resource
Expand acronym on the first use

SCORM was used without expansion.
Also, do we really "need" the copyright symbol on SCORM? Really?
4.1 Statement Properties
translate pulled
typo patch
Statement Properties: 4.1.1 ID, 4.1.2 Actor