v0.1.0.18: add "command" to PAGER
v0.1.0.19: create __blscd_edit_file() and keybinding E
v0.1.0.19: update README.md
v0.1.0.20: create __blscd_open_shell() and keybinding S
v0.1.0.20: update README.md
v0.1.1.0