Added a bunch of new features:

- Debug mode is now configurable in the configuration file. This way, we don't have to edit versioned files to disable it on production systems.
- Recent correspondents filter (enable in configuration file)
- Document actions: Edit tags and correspondents on multiple documents at once
- Replaced month list filter with date drilldown
- Sortable document count columns on Tag and Correspondent admin
- Last correspondence column on Correspondent admin
- Save and edit next functionality for document editing

requirements.txt

@@ -24,6 +24,7 @@ idna==2.7
 inotify-simple==1.1.8
 langdetect==1.0.7
 more-itertools==4.3.0
+numpy==1.15.1
 pdftotext==2.1.0
 pillow==5.2.0
 pluggy==0.7.1; python_version != '3.1.*'
@@ -45,6 +46,8 @@ pytz==2018.5
 regex==2018.8.29
 requests==2.19.1
 six==1.11.0
+scikit-learn==0.19.2
+scipy==1.1.0
 termcolor==1.1.0
 text-unidecode==1.2
 tzlocal==1.5.1