Partial rewrite of 4.1.4 Object

subsection 4.1.4.1 to follow. Was not changed because too complex. Need
some co-writing done on my own fork before commit can be made.

Notable differences in this one: switched the order of StatementRef and
Sub-Statements. Made more sense while writing the 'Rationale' and I
expect StatementRef to be used more frequently.
Merge pull request #24 from paul-esch/master

get paul master (right branch this time!)
Standardized headings in 4.1

For the third time....
Clarified examples
re-added link to verbs section

I guess this was removed accidentally
amended 4.1.4.3 rationale
commit just in case

Not sure if I changed anything with this commit!
Conversion fixes

Addressed some invalid 0.9 statements
Added conversion for non-URI extension keys
Merge branch 'master' of https://github.com/adlnet/xAPI-Spec
Fixed typo
Merge pull request #2 from garemoko/PaulObject

garemoko's suggested changes.
typos

minuscule typo and added code block quotes becaus Github wouldnt render.
quick fix to objectType in voided section
Merge branch 'master' of https://github.com/adlnet/xAPI-Spec
Update xAPI.md

grammar and wording clarifications in section 2
Update xAPI.md

grammar and wording improvements in section 1
Update xAPI.md

grammar and wording in section 3
normalized case of xAPI (replaced "XAPI" occurences)
Merge pull request #141 from bscSCORM/xapi

normalized case of xAPI (replaced "XAPI" occurences)
Update xAPI.md

grammar and wording in section 4.0 and 4.1 intro.