Microarchiver

* 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.

* Fix behavior when DataCite has no data for an article: `microarchiver` was _meant_ to flag the article and keep going, but instead it treated it as a fatal error.
* Fix some documentation errors about the numeric codes returned by `microarchiver`.
* Minor other improvements.

This version changes the behavior of the `-` command-line option, such that exceptions encountered when running with the `-` option do _not_ cause `microarchiver` to drop into an interactive debugger. The old behavior turned out to be unhelpful in practice, and moreover, it mixed two behaviors into one command-line flag. The latter was problematic when running `microarchiver` from scripts.

This version removes an unnecessary dependency on wxPython. A GUI interface was never completed for Microarchiver, and while the starting code is still in the code base in case we try to build a GUI, it doesn't have to be hooked in at this point. Removing the internal references to the GUI code allows the wxPython requirement to be removed, which in turn simplifies and speeds up installation.