Prompt fixes in zsh.

dotfiles/lib/bash/prompt.sh

@@ -0,0 +1,15 @@
+function current_directory() {
+    local PWD=$(pwd)
+    echo "${PWD/#$HOME/~}"
+}
+
+function git_prompt_info () {
+    if test -z $(parse_git_branch);
+    then
+        echo ""
+    else
+        echo "on $(parse_git_branch)"
+    fi
+}
+
+PS1='%u at $(hostname -s) in $(current_directory) $(git_prompt_info) $(colored_sandbox_string) '