[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/todo.py

@@ -0,0 +1,51 @@
+# pylint: disable=C0111,R0903
+
+"""Displays the number of todo items from a text file
+
+Parameters:
+    * todo.file: File to read TODOs from (defaults to ~/Documents/todo.txt)
+
+
+contributed by `codingo <https://github.com/codingo>`_ - many thanks!
+"""
+
+import os.path
+
+import core.module
+import core.widget
+import core.input
+
+
+class Module(core.module.Module):
+    def __init__(self, config, theme):
+        super().__init__(config, theme, core.widget.Widget(self.output))
+
+        self.__doc = os.path.expanduser(self.parameter("file", "~/Documents/todo.txt"))
+        self.__todos = self.count_items()
+        core.input.register(
+            self, button=core.input.LEFT_MOUSE, cmd="xdg-open {}".format(self.__doc)
+        )
+
+    def output(self, widget):
+        return str(self.__todos)
+
+    def update(self):
+        self.__todos = self.count_items()
+
+    def state(self, widgets):
+        if self.__todos == 0:
+            return "empty"
+        return "items"
+
+    def count_items(self):
+        try:
+            i = -1
+            with open(self.__doc) as f:
+                for i, l in enumerate(f):
+                    pass
+            return i + 1
+        except Exception:
+            return 0
+
+
+# vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4