[modules] Add "spacer"

Add a very, very basic module that simply adds a spacer (and empty
element) to the bar.

bumblebee/modules/spacer.py

@@ -0,0 +1,11 @@
+import bumblebee.module
+import bumblebee.util
+
+class Module(bumblebee.module.Module):
+    def __init__(self, args):
+        super(Module, self).__init__(args)
+
+    def data(self):
+        return ""
+
+# vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4