Roadmap
========================================
* [X] Support searching by properties
* [ ] Improve checkbox hierarchy
* [X] Support todo keyword faces
* [X] Support clocking work time
* [X] Improve folding
* [X] Support exporting (via existing emacs tools)
* [ ] Support archiving to specific headline
* [ ] Support tables
* [ ] Support diary format dates
* [ ] Support evaluating code blocks