Add timezoneJS to the JSHint allowed globals.

We trust that jquery.flot.time.js checks for timezoneJS's existence
before using it.

.jshintrc

@@ -14,6 +14,10 @@
 	"undef": true,
 	"unused": true,
 
+	"globals": {
+		"timezoneJS": true
+	},
+
 	"browser": true,
 	"jquery": true
 }