Added support for configuration to Roc.

The installer can now use a roc.cfg file to define the various needed modules.
Format:
{ "name": "demo", "location": ".",
  "modules": {
      "foo": { "location": "path-to-source-of-module-foo"; },
      "bar": { "location": "path-to-source-of-module-bar"; }
  }
}

tools/roc/roc.cfg-example

@@ -0,0 +1,24 @@
+{
+	"name": "demo",
+	"project": "demo-safe.ecf",
+	"location": ".",
+	"site_directory": "site",
+	"modules": {
+		"admin": 			{ "location": "../../modules/admin" },
+		"auth": 			{ "location": "../../modules/auth" },
+		"basic_auth": 		{ "location": "../../modules/basic_auth" },
+		"blog": 			{ "location": "../../modules/blog" },
+		"contact": 			{ "location": "../../modules/contact" },
+		"feed_aggregator": 	{ "location": "../../modules/feed_aggregator" },
+		"google_search": 	{ "location": "../../modules/google_search" },
+		"node": 			{ "location": "../../modules/node" },
+		"oauth20": 			{ "location": "../../modules/oauth20" },	
+		"openid": 			{ "location": "../../modules/openid" },
+		"recent_changes": 	{ "location": "../../modules/recent_changes" },
+		"seo": 				{ "location": "../../modules/seo" },
+		"session_auth": 	{ "location": "../../modules/session_auth" },
+		"taxonomy": 		{ "location": "../../modules/taxonomy" },
+		"files": 			{ "location": "../../modules/files" },
+		"custom_block": 	{ "location": "../../modules/custom_block" }
+	}
+}