Deferring rbenv init until we need it

since it appears to be the shell init hog.

bash_functions

@@ -154,6 +154,17 @@ function precmd(){
 }
 
 
-function unhyphenate(){
+function unhyphenate() {
     ruby -e "puts '$1'.gsub(/[\-_]/, ' ')"
 }
+
+
+function rbenv_init() {
+    if [ -n "$DEBUG" ] ; then
+        export RBENV_DEBUG=1
+        time eval "$(rbenv init -)"
+        unset RBENV_DEBUG
+    else
+        eval "$(rbenv init -)"
+    fi
+}