[FR] Sending the current line with its ANSI color codes preserved to the preview command

- [x] I have read through the manual page (`man fzf`)
- [x] I have the latest version of fzf
- [x] I have searched through the existing issues

## Info

- OS
- [ ] Linux
- [x] Mac OS X
- [ ] Windows
- [ ] Etc.
- Shell
- [ ] bash
- [x] zsh
- [ ] fish

## Problem / Steps to reproduce

I have created a [previewer](https://github.com/NightMachinary/ntom) that shows me searches from files in their context, but I lose the highlighting this way. It'd be great if you could support `{c}` to send the line with its color codes preserved to the previewer.