- fix almost all checkdoc problems. the rest I don't know how to fix.
- add git pre-commit hook

- merge lexical-binding line with file intro line
- allow capitalize zero in some docstring/error msg
- add "make pkg" this will create tar for package.el

user can toggle full-width mode via C-c , .
or they can set zero-full-width-mode in buffer or use setq-default to
set default value for all buffers.

updated the way keymap is configured.
switch to C-c , prefix according to minor-mode keybinding convention.