Add Fixtures.download_official_distribution to get binaries from apache.org
Download official binaries from apache.org for integration tests
Add resource templates for kafka 0.8.1.1 test fixtures
Use kafka_run_class_env() to set environment vars in test fixtures
Use travis env vars to run kafka version tests in parallel
Remove kafka src submodules
Add kafka 0.8.1.1 to integration tests.
- previous 0.8.1 src appears to have actually been 0.8.1.1
  based on git submodule commit.  So technically this adds back 0.8.1
  to the test suite.
Update tox.ini to use {posargs} to configure nosetests.
To override defaults, use
  `tox -- --your --nosetest --options --here`
Update default nosetest settings to use verbose logging and show test ids
add .coverage and .noseids to .gitignore
Add example for running single unit test to README
Increase fixture wait timeout to 30s; add wait-time logging
Support integration testing against kafka source builds (see README)
Merge pull request #193 from dpkp/test_apache_binary_release

Use Kafka Binaries for Integration Tests (Issue #176)
Add KafkaTimeoutError (used by client.ensure_topic_exists) and add a test