* Add FNM as an alternative to NVM
* Made the __bobthefish_prompt_nvm generic for nvm and fnm
* Hide errors on node_manager current
* Check for color_nvm and set color_node based on that
- Improve performance significantly in the base case (i.e. when git or something isn't slowing it down anyway).
- Make `bobthefish_display_colors` a non-underscore function. It's meant for public use :)
- Support previewing _different_ color schemes via `bobthefish_display_colors`. Pass a color scheme name, or `--all` to preview everything.
- Make color overrides a bit fishier: use a `bobthefish_colors` function to override color schemes, rather than declaring a whole pile of variables.
- Add support for a base color scheme in `bobthefish_colors`, in case you don't want to override everything.
- Add a deprecation notice with upgrade instructions for users with old-style custom color schemes.
