Merge pull request #49 from lsmith/master

Shuffling words. Clarifying? You be the judge.  (NOTE: Line 55 and its sub-bullets still need work, but will handle in another issue)
Add normative text and supporting note for how to deal with handler-returned promises
Remove trailing whitespace.
Return to original spec language and move prescriptive text to note
Allow values to be promises. Closes #53.
Merge remote-tracking branch 'origin/handler-promise-state'

Conflicts:
	README.md
Fix if/when and note ref nits. See #56
Fix markdown spacing
Work around jekyll rendering bug. See #56.
Minor updates to promise states wording
Fix #74. Clarify that all handlers must execute
Specify the `this` value must not be special. Closes #58.
Terminology clarification on "thenable" and "exception."

- Separate out "promise" and "thenable" concepts.
- Specify that "exception" just means "value".

The first of these helps greatly with the ambiguity of defining exactly what a promise is, versus the operational definition of a "thenable" as something that a promise consumes and assimilates if returned from a handler. The second helps clarify #65.
Add a conformant implementations list.

Closes #59, closes #57.
Move "must not change" definition into relevant section.

It looked pretty out of place among the rest of the terms.
Use relative links, now that GitHub supports it.

See https://github.com/blog/1395-relative-links-in-markup-files.
Use fenced code blocks, now that GitHub pages support them.

See https://github.com/blog/1366-github-pages-updated-to-jekyll-0-12-0.
`undefined` is code, mark it as such.
Added Naive Promesse
Add promise-as3 and P implementations.