Move some private vim undo/backup paths out of vimrc and into a sourced file

osx/install.sh

@@ -1,23 +1,6 @@
 #!/bin/bash
 
-if which tput >/dev/null 2>&1; then
-  ncolors=$(tput colors)
-fi
-if [ -t 1 ] && [ -n "$ncolors" ] && [ "$ncolors" -ge 8 ]; then
-  RED="$(tput setaf 1)"
-  GREEN="$(tput setaf 2)"
-  YELLOW="$(tput setaf 3)"
-  BLUE="$(tput setaf 4)"
-  BOLD="$(tput bold)"
-  NORMAL="$(tput sgr0)"
-else
-  RED=""
-  GREEN=""
-  YELLOW=""
-  BLUE=""
-  BOLD=""
-  NORMAL=""
-fi
+source "../script_helpers/printing.sh"
 
 set -e