Fix tests_stubs tests

Minor fixes for api changes from a while ago.
Since the "tests_stubs" directory starts with "tests_", it isn't/wasn't
run automatically by nosetests when the code was changed.
Add "enable_retries" to run_queue()
Make sure to increment the eta

We are ignoring the eta, but when app engine postpones a task for
a retry, it verifies the eta has increased.
More comprehensive test for retries

Ensure the retry parameter is tracked separately for tasks.
No new failures, but this better verifies that retries with the
queue runner are working.
Fix bool docstrings
Readd param description to docstrings
Add param docstrings for the two new functions
Merge pull request #124 from ericolson-wf/add_retries_to_test_runner

Add retries to test runner
Logging tweaks
Merge branch 'master' into notify_task_info

* master:
  Add param docstrings for the two new functions
  Readd param description to docstrings
  Fix bool docstrings
  More comprehensive test for retries
  Make sure to increment the eta
  Add "enable_retries" to run_queue()
  Fix tests_stubs tests
Switch _get_context_id to match persistence branch implementation

Switch the _get_context_id to match the same function in the persistence branch
to get out ahead of a merge conflict.