general cleanup.  Added a stack-trace to logging in deamon.py
if a tag has an empty blob (apparently it can happen), it errors out.  this is a fix for that.
version bump
bug in logging
version fix
fixed very odd race condition bug where it was possible to read a corruped pid.last_run file while the child process was writing it
doc: fix some indentations
job: add checkmarks to avoid re-doing a stage if there is a failure
Merge pull request #18 from pooya/checkmark

Checkmark
Revert "job: add checkmarks to avoid re-doing a stage if there is a failure"

This reverts commit 68002d6f7d0a033e4a344c17c33a948540639b6c.

The checkmark mechanism cannot handle jobs with the same name. Solving this
issue requires much more logic that makes the code more complicated.
examples: add an example for dependencies
Merge pull request #19 from pooya/master

revert checkmark changes
job: add an exponential backoff for retrying actions after a failure
Merge pull request #20 from pooya/master

job: add an exponential backoff for retrying actions after a failure
job: add the exception message to the logs when claiming disco job has failed
handle empty blob lists from disco

cherry-picked from a pull request
Merge pull request #21 from pooya/master

handle empty blob lists from disco
bump the version to 0.2.39
support custom dialect/delimiter for csv reader
inferno retry functionality

Conflicts:
	inferno/lib/daemon.py
	inferno/lib/pid.py