Merge pull request #4 from adlnet/master

update from adl master
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
Required columns on tables From 4.1.4.1 down to 4.1.5
Add missing table heading on Interaction components
Endpoint in example incorrectly included / on the end as well as capital S

Fixed to /statements instead of /Statements/
Fix resource listed in Appendix A

Remove capital "S" and trailing "/".
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?
Merge pull request #421 from garemoko/post-json-objects

Post json objects
Merge pull request #430 from drozzy/patch-1

Expand acronym on the first use
Merge pull request #426 from brianjmiller/patch-1

Fix resource listed in Appendix A
Merge pull request #428 from brianjmiller/patch-5

7.7 Correct capitalization of property in /about resource
Merge pull request #425 from fugu13/incorrectendpoint

Endpoint in example incorrectly included / on the end as well as capital S
Merge pull request #423 from phamdt/mbox_links

fixed mbox related links
Merge pull request #422 from garemoko/requiredtables

Add optional/required for a number of tables
fixes in response to @andyjohnson comments

fixes https://github.com/adlnet/xAPI-Spec/pull/424#discussion_r8100299 , https://github.com/adlnet/xAPI-Spec/pull/424#discussion_r8100339 , https://github.com/adlnet/xAPI-Spec/pull/424#discussion_r8100345
Addresses https://github.com/adlnet/xAPI-Spec/pull/424#discussion_r6925553