Update README.md

Modified title
Update README.md
Updated content to replace guidelines with standards

Given that this will be a standard for us and not a guideline the content should be updated accordingly.
Updated the table of content at top

Forgot to update the toc.
Merge pull request #11 from wardi/limits

Pulling in these changes prior to Sam working on the document today.

Tonight I've got a block of time to reword the Language and this Offset block.

This is good and will be part updates we mention at WMC
Added guidance around HTTP Header "Accept:"

API Version and Content Negotiation should be done through the HTTP Header "Accept" instead of defining it through the URL
Language standardizing, softer "should" to be replaced with "shall" in the standard.  Language to stay softer while open participation is promoted.
Offset logic from Ian Ward (GitHub.org @wardi) re-introduced with more general definiton of offsets.
Clarification on language to account for both Laurent Goderre (GitHub @LaurentGoderre) and Ian Ward's @wardi's recomendations.
Re-organized sections, more of that could be done.
Two sections tagged for removal, confusing and competing.
Two new sections to be populated.

More examples required.
More revision required.

This version should be promoted to the WIWG for review prior to WMC.
Can't comment out markdown, was to be removed, removed.