Roll our own feature list and release list...

It's crazy insane faster: https://gist.github.com/06c5b660da4a2cdeba09
diff --git a/git-flow-completion.bash b/git-flow-completion.bash
index aea0c4c..989882c 100755
--- a/git-flow-completion.bash
+++ b/git-flow-completion.bash
@@ -107,7 +107,8 @@
 
 __git_flow_list_features ()
 {
-	git flow feature list 2> /dev/null | tr -d ' |*'
+	local prefix="$(__git_flow_feature_prefix)"
+	git branch 2> /dev/null | tr -d ' |*' | grep "^$prefix" | sed s,^$prefix,,
 }
 
 __git_flow_list_remote_features ()
@@ -144,7 +145,13 @@
 
 __git_flow_list_releases ()
 {
-	git flow release list 2> /dev/null
+	local prefix="$(__git_flow_release_prefix)"
+	git branch 2> /dev/null | tr -d ' |*' | grep "^$prefix" | sed s,^$prefix,,
+}
+
+__git_flow_release_prefix ()
+{
+	git config gitflow.prefix.release 2> /dev/null || echo "release/"
 }
 
 __git_flow_hotfix ()