Listing all entries in DayOne Classic journal throws IndexError (#786)

* Reproduce bug in #780
🎵 I have no body, no body to love me... 🎵
The bug is cause by a DayOne entry that has to entry body.

* Deal with empty bodies
Close #780.

* [Travis-CI] add "tree" command to debug missing files
* Fix file location
I have no idea why, but it ran locally fine without issue. Travis is more particular...

.travis.yml

@@ -9,8 +9,14 @@ git:
   depth: false
   autocrlf: false
 
+addons:
+  apt:
+    packages:
+      - tree
+
 before_install:
   - date
+  - tree
 
 install:
   - pip install poetry