Refactor: main_buffer -> buffer
Implement zoom feature for TextEdit
Make path_entry selectable
Note about mouse wheel event
Add design ideas
Add create_dir and mkdir
Add command type as eval_text result
Add feature about command log
UI design changed: directory_buffer -> shell_buffer
Now path_entry is just a label which couldn't be changed to an entry
Correct TextEdit UX design
Corrent mockup
Add method to remove margins
Fix set_no_margins typo
Correct TextEdit code to match UX design
MainWindow has no margins
Add access to current shell buffer
Fix shell command not return command_type when prefixing !
shell_buffer auto-show when shell command is executed