bugs/issues
  - backspace in run_c draws border when buffer is outside run_x
  - submenu dims are inherited from parent dims

v1.0.0 features
  - builtin function to display all user-mapped commands
  - builtin function to quickedit pshd file using $EDITOR
  - make install

Backlog
  - optional single menu mode [launch into a menu]
  - full command list option
  - ability to pass args to commands
  - Scale menu sizes to longest menu entry
  - consume config function
  - remove END_OF_MENU requirement by introducing vector structures
    - alternatively a config parser

