[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/arch-update.py

@@ -0,0 +1,50 @@
+"""Check updates to Arch Linux.
+
+Requires the following executable:
+    * checkupdates (from pacman-contrib)
+
+contributed by `lucassouto <https://github.com/lucassouto>`_ - many thanks!
+"""
+
+import logging
+
+import core.module
+import core.widget
+import core.decorators
+
+import util.cli
+
+
+class Module(core.module.Module):
+    @core.decorators.every(minutes=60)
+    def __init__(self, config, theme):
+        super().__init__(config, theme, core.widget.Widget(self.utilization))
+        self.__packages = 0
+        self.__error = False
+
+    @property
+    def __format(self):
+        return self.parameter("format", "Update Arch: {}")
+
+    def utilization(self, widget):
+        return self.__format.format(self.__packages)
+
+    def hidden(self):
+        return self.__packages == 0 and not self.__error
+
+    def update(self):
+        try:
+            result = util.cli.execute("checkupdates")
+            self.__packages = len(result.split("\n")) - 1
+            self.__error = False
+        except Exception as e:
+            logging.exception(e)
+            self.__error = True
+
+    def state(self, widget):
+        if self.__error:
+            return "warning"
+        return self.threshold_state(self.__packages, 1, 100)
+
+
+# vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4