Adds base16-fish-shell

[FabioAntunes]

A pure fish shell solution to change your shell's default ANSI colours but most importantly, colours 17 to 21 of your shell's 256 colorspace (if supported by your terminal). This script makes it possible to honour the original bright colours of your shell (e.g. bright green is still green and so on) while providing additional base16 colours to applications such as Vim.

Heavily inspired on Base16 Shell