Add new theme: Molokai

Add Molokai theme

This color scheme is based off of [molokai](https://github.com/tomasr/molokai) for vim.

This theme is similar to the Monokai Soda theme, but it makes various usability improvements by __staying more true__ to the original ANSI colors.

Specifically, Molokai differs from Monokai Soda in the following major ways: 

- The third color (33, 34), which is traditionally _yellow_, is a pastel yellow compared with orange (33) and yellow (43)
- The fourth color (34, 44), which is traditionally _blue_, is a pastel blue compared with a lavender purple
- The fifth color (35, 45), which is traditionally _magenta_, is a pastel purple compared with a (repeated) pink color
- The background color is slightly darker