Some colorschemes are outdated?

It seems, that some of the provided colorschemes (in my case: [Iceberg](http://www.vim.org/scripts/script.php?script_id=4820) don't use the newest version of said colorscheme.

Here is the [`diff`](https://gist.github.com/redtrumpet/bd883d7e1e512698e9bac3315bf3d5f1) between the provided `iceberg.vim` and the one provided by the official repository.

What is the standard procedure to update colorschemes?

Start with the provided iceberg.vim file and compare it with the official Iceberg repository using the linked diff. Check how colorschemes are organized in this repository and determine the expected update procedure. Done means the bundled Iceberg scheme matches the intended upstream version.

Written by the indexing model from the issue text.