Make colordiff use the --unified format

dotfiles/bash/host/azzgoat.bashrc

@@ -19,7 +19,7 @@ alias  tap-reader="./node_modules/tap/bin/tap-reader.js"
 alias vim='~/bin/vim-bx.pl'
 
 alias Markdown='~/bin/Markdown'
-alias diff="colordiff"
+alias diff="colordiff -u"
 
 # from minions
 alias autotest.pl='~/bin/autotest.pl'