Pubarchiver

* Test for more signs of failure in `upload-to-pmc.sh`.
* Make some very tiny tweaks to the format of logs.

* Assume the use of Python `virtualenv` to lock in a specific Python environment.
* Fix a bug in one of the workflow scripts in which the lack of a mail message body caused the mail command to hang indefinitely.

* Add new helper function to run `curl` in the upload script for PMC.
* Fix inconsistency in the PMC upload script, wherein the user and password variables were not the same name as the cron variables actually used.

* Fix bug in date handling in workflow scripts. The value of the `--after-date` argument to `microarchiver` was set to the date it ran, which caused it to miss articles published on the date that it ran. The value of the date should have been modified to include the day it last ran so that the date comparison was correct. (Thanks to Nick Stiffler for catching and reporting the problem.)

(Mistaken release -- ignore this.)

* Update the workflow scripts and associated crontab template.