misc: Add two scripts to help debug things

This adds two new helper scripts that are good for debugging mgmt. Just
build and add `sigtee` to your ~/bin/ along with filter-golang-stack.py
and mgmt_debug.sh and use the later to call mgmt as you would normally.

For example, I might do:

$ mgmt_debug.sh ./mgmt run --tmp-prefix lang examples/lang/hello0.mcl

And if I kill it with ^\ then I'll get a filtered trace at the end in my
$PAGER (which is assumed to be `less`) and this should make my life
easier.

As a cool bonus, this means we use bash, python, and golang all
together!

misc/mgmt_debug.sh

@@ -0,0 +1,31 @@
+#!/bin/bash
+
+# This is a helper script to run mgmt and capture and filter stack traces. Any
+# time mgmt crashes with a trace, it will first be filtered, and then displayed
+# with `less`.
+
+f1=`mktemp /tmp/tmp.X'X'X`
+f2=`mktemp /tmp/tmp.X'X'X`
+
+# run the program until it ends
+# XXX: we need an --ignore-exit signal blocker too so we can ^\
+#$@ 2>&1 | tee --ignore-interrupts --ignore-exit "$f1"
+$@ 2>&1 | sigtee "$f1"
+
+# clean up when we're done
+function cleanup {
+	filter-golang-stack.py "$f1" > "$f2"
+	if [ $? -eq 0 ]; then
+		less "$f2"
+	fi
+	if [ "$1" = "--preserve" ]; then
+		echo "logged:"
+		echo "$f1"
+		echo "$f2"
+	else
+		rm "$f2"
+		rm "$f1"
+	fi
+
+}
+trap cleanup EXIT