[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/taskwarrior.py

@@ -0,0 +1,41 @@
+"""Displays the number of pending tasks in TaskWarrior.
+
+Requires the following library:
+    * taskw
+
+Parameters:
+    * taskwarrior.taskrc : path to the taskrc file (defaults to ~/.taskrc)
+
+
+contributed by `chdorb <https://github.com/chdorb>`_ - many thanks!
+"""
+
+from taskw import TaskWarrior
+
+import core.module
+import core.widget
+import core.decorators
+
+
+class Module(core.module.Module):
+    def __init__(self, config, theme):
+        super().__init__(config, theme, core.widget.Widget(self.output))
+
+        self.__pending_tasks = "0"
+
+    def update(self):
+        """Return a string with the number of pending tasks from TaskWarrior."""
+        try:
+            taskrc = self.parameter("taskrc", "~/.taskrc")
+            w = TaskWarrior(config_filename=taskrc)
+            pending_tasks = w.filter_tasks({"status": "pending"})
+            self.__pending_tasks = str(len(pending_tasks))
+        except:
+            self.__pending_tasks = "n/a"
+
+    def output(self, _):
+        """Format the task counter to output in bumblebee."""
+        return "{}".format(self.__pending_tasks)
+
+
+# vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4