Adding multiple SCM support to doubletime theme.

The doubletime theme improves the SCM status prompt for git.
However, it accomplishes this at the expense of other SCM
systems. This delegates prompt to the default bash-it prompt
function when the SCM is not git.
diff --git a/themes/doubletime/doubletime.theme.bash b/themes/doubletime/doubletime.theme.bash
index 1237f80..e16ba66 100644
--- a/themes/doubletime/doubletime.theme.bash
+++ b/themes/doubletime/doubletime.theme.bash
@@ -17,11 +17,12 @@
 
 doubletime_scm_prompt() {
   CHAR=$(scm_char)
-  if [ $CHAR = $SCM_NONE_CHAR ]
-  then
+  if [ $CHAR = $SCM_NONE_CHAR ]; then
     return
-  else
+  elif [ $CHAR = $SCM_GIT_CHAR ]; then
     echo "$(git_prompt_status)"
+  else
+    echo "[$(scm_prompt_info)]"
   fi
 }