Add aliases for `git lg`.

As documented in <https://coderwall.com/p/euwpig> and pointed out by
@dracos.
Add Solarized colour scheme for Vim.

Source repo: git@github.com:altercation/vim-colors-solarized.git
Source commit: 528a59f26d12278698bb946f8fb82a63711eec21
Add Solarized schemes to iTerm and use Dark.
Activate Solarized Dark in Vim.
Remove explicit colouring on `ColorColumn`.

Solarized handles this now.
Merge branch 'solarized'