tests: Big push to get the tests to pass again. - Lots of fixes everywhere in the code. - Try to handle debug logging in the multiprocessing worker pool when running in pytest. Not perfect, but usable for now. - Replace all `.md` test files with `.html` since now a auto-format extension always sets the format. - Replace `out` with `outfiles` in most places since now blog archives are added to the bake output and I don't want to add expected outputs for blog archives everywhere.

--- a/piecrust/data/paginationdata.py	Sun Oct 29 22:46:41 2017 -0700
+++ b/piecrust/data/paginationdata.py	Sun Oct 29 22:51:57 2017 -0700
@@ -51,7 +51,7 @@
 
 
 def _load_datetime(data, name):
-    dt = data_page.datetime
+    dt = data._page.datetime
     return {
         'year': dt.year, 'month': dt.month, 'day': dt.day,
         'hour': dt.hour, 'minute': dt.minute, 'second': dt.second}