emacs: use amx and flx instead prescient in ivy
emacs: change some variable define
fix
emacs: mu4e new packages
mu4e instead of wanderlust
emacs: mail
emacs: use irc and mail, remove mutt and offlineimap and weechat and msmtp
fix bugs
emacs & nixos
emacs: engine mode
a lot of fix
nixos: change merge & change shell
nixos: overlay fix
fix font and reuse fira code use fontconfig dpi to adjust font size
remove fira code and restruct files in nixos dir