Support quoting behavior of bash 4.3+

bash 4.2 will print literal tilde, which seems like least evil.

dotfiles/bash/post.bashrc

     xterm*|rxvt*|screen*)
         test -n "$SSH_CONNECTION" \
          && __host_id="${HOSTNAME%%.*}:"      # i.e. a remote session
-        PROMPT_COMMAND='__save_rv $?; echo -ne "\033]0;$(__make_ps1d)$__host_id${PWD/$HOME/~}\$\007"'
+        PROMPT_COMMAND='__save_rv $?; echo -ne "\033]0;$(__make_ps1d)$__host_id${PWD/$HOME/\~}\$\007"'
 
         # Show the currently running command in the terminal title:
         # http://www.davidpashley.com/articles/xterm-titles-with-bash.html
                     # output them.
                     ;;
                 "")
-                    echo -ne "\033]0;$(__make_ps1d)$__host_id${PWD/$HOME/~}\$\007"
+                    echo -ne "\033]0;$(__make_ps1d)$__host_id${PWD/$HOME/\~}\$\007"
                     ;;
                 *)
-                    echo -ne "\033]0;${BASH_COMMAND} ($__host_id${PWD/$HOME/~})\007"
+                    echo -ne "\033]0;${BASH_COMMAND} ($__host_id${PWD/$HOME/\~})\007"
                     ;;
             esac
         }