Exit jrnl if no text entered into editor

Add test for aborting jrnl entry from editor
Use native mocking
Add comment explaining discrepancy between expected and asserted output
Fix check_empty_output method
Check message on stderr and patch subprocess.call
Add _mock_editor_function
Update features/steps/core.py
Add return from mock function
Add debug statements
Debug
Update features/steps/core.py
Move sys.exit() down
Fix test?
Fix test?
Fix test?
Clean up debug statements
Clean up debug statements
Remove extraneous code
Remove extra space
Add test for empty stdin input
Remove extra debug line
Fix test?
Fix test?
Update features/core.feature
Fix test?
Fix no stdin input test

Co-Authored-By: pspeter <peter.schmidb@gmail.com>

features/data/configs/editor.yaml

@@ -0,0 +1,12 @@
+default_hour: 9
+default_minute: 0
+editor: "vim"
+encrypt: false
+highlight: true
+journals:
+  default: features/journals/simple.journal
+linewrap: 80
+tagsymbols: "@"
+template: false
+timeformat: "%Y-%m-%d %H:%M"
+indent_character: "|"