.vimrc: add syntax highlighting for Go (golang)
.zsh: only remove one docker image at a time when calling dkr-remove-test-images
.zsh: add dkr-install() function
.vimrc: add ctags support
.gitconfig: effortless ctags in git projects

See: http://tbaggery.com/2011/08/08/effortless-ctags-with-git.html
.zsh: remove 'echo' from a docker alias