Add DevTools as submodule, build DevTools for Travis Test

tests/travis.sh

@@ -0,0 +1,30 @@
+#!/bin/bash
+
+PHP_BINARY="php"
+
+while getopts "p:" OPTION 2> /dev/null; do
+	case ${OPTION} in
+		p)
+			PHP_BINARY="$OPTARG"
+			;;
+	esac
+done
+
+./tests/lint.sh -p "$PHP_BINARY"
+
+if [ $? -ne 0 ]; then
+	echo Lint scan failed!
+	exit 1
+fi
+
+cp -r tests/plugins plugins
+"$PHP_BINARY" ./plugins/PocketMine-DevTools/src/DevTools/ConsoleScript.php --make ./plugins/PocketMine-DevTools --relative ./plugins/PocketMine-DevTools --out ./plugins/DevTools.phar
+rm -rf ./plugins/PocketMine-DevTools
+
+echo -e "version\nmakeserver\nstop\n" | "$PHP_BINARY" src/pocketmine/PocketMine.php --no-wizard --disable-ansi --disable-readline --debug.level=2
+if ls plugins/DevTools/PocketMine*.phar >/dev/null 2>&1; then
+    echo Server phar created successfully.
+else
+    echo No phar created!
+    exit 1
+fi