Use first line of docstring as command title
Make Editor.file_path writable and add Editor.app
Add diff command
Add support for diff with other file
Move test utilities to separate package (testil)
Bugfix: error on open document via File > Open
Add *.mm to ObjectiveC syntax definition
Add tooltip to Python Replace checkbox

...in Find panel.
Fix broken mocker dependency with patched version
Update change log
Prepare for 1.4.0 release
Moved Editor class into its own module
Eliminate global app singleton (editxt.app)
Refactor test_app as class
Rename test_app.config to test_app.state