Corrects errors in 0.9.15.2 tasks restarting on tx timeouts/unavailable

[djjolicoeur]

@lbradstreet it looks like I missed a few things in the 0.9.15.2 branch that prevented the tasks from being restarted. I honestly wasn't expecting for it to be merged straight away!!

in this branch:

• fix the issue with detecting when the exceptions we are restarting on are thrown in the bulk datoms output tasks.
• made detecting the exceptions in the first place more robust
• added tests for the above
• added tests around the write-batch implementation for each output and make sure the restart code is working properly, given the appropriate exceptions and behaves as it did before, otherwise.

Sorry for taking up your time with an unsupported branch, but if you could cut a release, it would be helpful to us as we transition to 0.14.x.

Speaking of, for 0.14.x, I am going to add something to the information model to make this restartable behavior optional, I think. I can imagine some folks might not want to reboot the task on those conditions. I have started working on that branch already and, hopefully, will have that to you soon.

[djjolicoeur]

@lbradstreet was wondering if you had a chance to look at this yet? If it's going to be a while, I can deploy a jar from out fork under our com. for the time being for my folks to use.

Still working on 0.14.x