Whitespace, consistent formatting
Document request formats

- Add some top-level headings to the README
- Document route formats and provide example requests.
Fix indentation

We want the URLs to be monospaced.
Monospace references to route parameters
Document WHAT IT IS
Document why you'd use it
Refer to a user's identifier as such
Style: one sentence per line
Remove superfluous 'Setup' heading
Update README.md

Add some more content.
README revisions

- Better explain the use case
- Reword some sentences
- Style: sentences on separate lines
- Style: no newline after headers
Update examples to use API domain
Smaller headers for setup copy
Add example markup with Haml
Rephrase AMUSING INTERROGATIVE
Use paren-style syntax for Haml attributes
Use allowed dimensions in example URL

Although unusual, I'm requesting a rectangular avatar to disambiguate
the ordering of height and width in the URL.
Merge pull request #5 from adorableio/documentate

Updated README