[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/amixer.py

@@ -0,0 +1,51 @@
+"""get volume level
+
+Parameters:
+    * amixer.device: Device to use, defaults to "Master,0"
+
+contributed by `zetxx <https://github.com/zetxx>`_ - many thanks!
+"""
+import re
+
+import core.module
+import core.widget
+
+import util.cli
+
+
+class Module(core.module.Module):
+    def __init__(self, config, theme):
+        super().__init__(config, theme, core.widget.Widget(self.volume))
+
+        self.__level = "n/a"
+        self.__muted = True
+        device = self.parameter("device", "Master,0")
+        self._cmdString = "amixer get {}".format(device)
+
+    def volume(self, widget):
+        if self.__level == "n/a":
+            return self.__level
+        m = re.search(r"([\d]+)\%", self.__level)
+        self.__muted = True
+        if m:
+            if m.group(1) != "0" and "[on]" in self.__level:
+                self.__muted = False
+            return "{}%".format(m.group(1))
+        else:
+            return "0%"
+
+    def update(self):
+        try:
+            self.__level = util.cli.execute(
+                "amixer get {}".format(self.parameter("device", "Master,0"))
+            )
+        except Exception as e:
+            self.__level = "n/a"
+
+    def state(self, widget):
+        if self.__muted:
+            return ["warning", "muted"]
+        return ["unmuted"]
+
+
+# vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4