facts: boolean to display facts items in view

carried over from the choices functionality that always does this, make
this an option for the FactCategory for when we have views

bss/dr.botzo#15

facts/migrations/0006_factcategory_show_all_entries.py

@@ -0,0 +1,20 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.10.5 on 2017-02-11 15:00
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('facts', '0005_auto_20150814_1653'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='factcategory',
+            name='show_all_entries',
+            field=models.BooleanField(default=False),
+        ),
+    ]