Fix --version flag to print version again (#124)

Fixes #123
diff --git a/main.js b/main.js
index 1ae9167..c1314a5 100755
--- a/main.js
+++ b/main.js
@@ -44,7 +44,7 @@
     platform_name: knownPlatforms,
     project: path,
     plugin: [String, path, url, Array],
-    version: String,
+    version: Boolean,
     help: Boolean,
     debug: Boolean,
     silent: Boolean,