vim: don't open a new split for editing vimrc, just open it
mpv: disable softvol
gitconfig: set abbrev = 9
vimrc: many updates

- <cr> -> <CR>
- Various organization
- Replaced autoreload of vimrc by manual reload
- Various new mappings
- Unset gdefault: makes searching over only text selections impossible
- Use shortform of autocmd, au