Make CI build flatter (and therefore faster) (#123)

Now with a fancier script for running h2spec
will ensure that the server executable is killed when h2spec finishes,
de-interleaves h2spec & example server stdout

ci/h2spec.sh

@@ -0,0 +1,28 @@
+#!/bin/bash
+LOGFILE="h2server.log"
+
+if ! [ -e "h2spec" ] ; then
+    # if we don't already have a h2spec executable, wget it from github
+    wget https://github.com/summerwind/h2spec/releases/download/v2.1.0/h2spec_linux_amd64.tar.gz
+    tar xf h2spec_linux_amd64.tar.gz
+fi
+
+cargo build --example server
+exec 3< <(./target/debug/examples/server);
+SERVER_PID=$!
+
+# wait 'til the server is listening before running h2spec, and pipe server's
+# stdout to a log file.
+sed '/listening on Ok(V4(127.0.0.1:5928))/q' <&3 ; cat <&3 > "${LOGFILE}" &
+
+# run h2spec against the server, printing the server log if h2spec failed
+./h2spec -p 5928
+H2SPEC_STATUS=$?
+if [ "${H2SPEC_STATUS}" -eq 0 ]; then
+    echo "h2spec passed!"
+else
+    echo "h2spec failed! server logs:"
+    cat "${LOGFILE}"
+fi
+kill "${SERVER_PID}"
+exit "${H2SPEC_STATUS}"