* Ray doc - changed python indentation to 4 spaces in documentation files actors.rst, api.rst, and example-*.rst
* Ray documentation - changed Python to 4 space indentation for files install-*.rst, installation-troubleshooting.rst, internals-overview.rst, serialization.rst, troubleshootin.rst, tutorial.rst, using-ray-*.rst
* Perform ray.register_class under the hood.
* Fix bug.
* Release worker lock when waiting for imports to arrive in get.
* Remove calls to register_class from examples and tests.
* Clear serialization state between tests.
* Fix bug and add test for multiple custom classes with same name.
* Fix failure test.
* Fix linting and cleanups to python code.
* Fixes to documentation.
* Implement recursion depth for recursively registering classes.
* Fix linting.
* Push warning to user if waiting for class for too long.
* Fix typos.
* Don't export FunctionToRun if pickling the function fails.
* Don't broadcast class definition when pickling class.
* Serialize lambdas with pickle by default.
* Serialize sets with pickle by default.
* Serialize types with pickle by default.
* Small update to documentation.
* Update tests.
