[core] restructure to allow PIP packaging

OK - so I have to admit I *hate* the fact that PIP seems to require a
subdirectory named like the library.

But since the PIP package is something really nifty to have (thanks to
@tony again!!!), I updated the codebase to hopefully conform with what
PIP expects. Testruns so far look promising...

bumblebee_status/modules/contrib/xkcd.py

@@ -0,0 +1,25 @@
+# pylint: disable=C0111,R0903
+
+"""Opens a random xkcd comic in the browser.
+
+contributed by `whzup <https://github.com/whzup>`_ - many thanks!
+"""
+
+import core.module
+import core.widget
+import core.input
+import core.decorators
+
+
+class Module(core.module.Module):
+    @core.decorators.never
+    def __init__(self, config, theme):
+        super().__init__(config, theme, core.widget.Widget("xkcd"))
+        core.input.register(
+            self,
+            button=core.input.LEFT_MOUSE,
+            cmd="xdg-open https://c.xkcd.com/random/comic/",
+        )
+
+
+# vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4