Add capability necessary for untarring.
Fix a large number of problems which show up on bare vagrant boxes:

* Agent log port is randomly assigned.
* Added KEEP_ARTIFACTS flag to facilitate debugging.
* Added dependencies to container which are necessary for download process.
* Added dependencies to container to facilitate debugging within the container.
HTTPD killing now uses same method as agent and scheduler killing.
Several changes to basic_test.

* Explicitly starts container.
* Correctly initializes port for warhead.
* Contains methods for observing supervisor state.
* Extract ID into a variable.
Fix blocking in agent when logs are streamed.
Merge branch 'fix-blocking-log-call' into use-warhead
Report stderr when untarring artifacts.
Merge branch 'make-tar-more-verbose' into use-warhead
Added log generation to warhead.
Adding KILL capability allows agent and supervisor to shut down containers.
Changed termination methods for debugging functions.
Removed dynamic logging port which causes logging API to break. See Issue #159.
Re-enabled Failed Creation test.
Revert mistaken change.
Fix some SimpleHTTPD related startup and shutdown issues.