Adding utf-8 support
Fixing stupid encode mistake
Adding test case for strings with accent chars
Add a summary of pyelasticsearch's philosophy to the dev docs page.

Making explicit pyelasticsearch's guiding principles are important for my own clarity of thought as much as for any other reason.
Correct support for unicode URL path components and query string param values.

Add test coverage to make sure unicode field values work properly.
Support Unicode URL path components (like document IDs) and query string param values. Fix #94.