Authority requirement cleanup

Pulled out some of the more basic requirements for authority to the top of the section.

The rest probably could still use some re-formating, but I suggest this is a useful step worth merging, since it pulls some important points to the top.
Merge pull request #91 from paul-esch/master

rewrite of 3.1.4 Verb, and a small note to the not-so-technical readers.
Merge pull request #90 from bscSCORM/authority

Authority requirement cleanup
Merge branch 'master' of https://github.com/adlnet/xAPI-Spec