Fix example code in README.md

To upload file, `curl` requires `@` at the beginning of file path.
Merge pull request #532 from tricknotes/fix-example-in-readme

Fix example code in README.md
Evaluate auth blocks with endpoint instance as context
Make helpers available to middleware (e.g. auth blocks)
Ignore .project files
Use Ruby 1.9 hash syntax and removed whitespace
Test that the endpoint and helper methods are available in auth callbacks
Fixed tests for basic auth
Merge branch 'master' of https://github.com/wellthie/grape