[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/core/ping.py

@@ -0,0 +1,95 @@
+# pylint: disable=C0111,R0903
+
+"""Periodically checks the RTT of a configurable host using ICMP echos
+
+Requires the following executable:
+    * ping
+
+Parameters:
+    * ping.address : IP address to check
+    * ping.timeout : Timeout for waiting for a reply (defaults to 5.0)
+    * ping.probes  : Number of probes to send (defaults to 5)
+    * ping.warning : Threshold for warning state, in seconds (defaults to 1.0)
+    * ping.critical: Threshold for critical state, in seconds (defaults to 2.0)
+"""
+
+import re
+import time
+import threading
+
+import core.module
+import core.widget
+import core.event
+import core.decorators
+
+import util.cli
+
+
+def get_rtt(module, widget):
+    try:
+        widget.set("rtt-unreachable", False)
+        res = util.cli.execute(
+            "ping -n -q -c {} -W {} {}".format(
+                widget.get("rtt-probes"),
+                widget.get("rtt-timeout"),
+                widget.get("address"),
+            )
+        )
+
+        for line in res.split("\n"):
+            if line.startswith(
+                "{} packets transmitted".format(widget.get("rtt-probes"))
+            ):
+                m = re.search(r"(\d+)% packet loss", line)
+
+                widget.set("packet-loss", m.group(1))
+
+            if not line.startswith("rtt"):
+                continue
+            m = re.search(r"([0-9\.]+)/([0-9\.]+)/([0-9\.]+)/([0-9\.]+)\s+(\S+)", line)
+
+            widget.set("rtt-min", float(m.group(1)))
+            widget.set("rtt-avg", float(m.group(2)))
+            widget.set("rtt-max", float(m.group(3)))
+            widget.set("rtt-unit", m.group(5))
+    except Exception as e:
+        widget.set("rtt-unreachable", True)
+
+    core.event.trigger("update", [module.id], redraw_only=True)
+
+
+class Module(core.module.Module):
+    @core.decorators.every(seconds=60)
+    def __init__(self, config, theme):
+        super().__init__(config, theme, core.widget.Widget(self.rtt))
+
+        widget = self.widget()
+
+        widget.set("address", self.parameter("address", "8.8.8.8"))
+        widget.set("rtt-probes", self.parameter("probes", 5))
+        widget.set("rtt-timeout", self.parameter("timeout", 5.0))
+        widget.set("rtt-avg", 0.0)
+        widget.set("rtt-unit", "")
+        widget.set("packet-loss", 0)
+
+    def rtt(self, widget):
+        if widget.get("rtt-unreachable"):
+            return "{}: unreachable".format(widget.get("address"))
+        return "{}: {:.1f}{} ({}%)".format(
+            widget.get("address"),
+            widget.get("rtt-avg"),
+            widget.get("rtt-unit"),
+            widget.get("packet-loss"),
+        )
+
+    def state(self, widget):
+        if widget.get("rtt-unreachable"):
+            return ["critical"]
+        return self.threshold_state(widget.get("rtt-avg"), 1000.0, 2000.0)
+
+    def update(self):
+        thread = threading.Thread(target=get_rtt, args=(self, self.widget(),))
+        thread.start()
+
+
+# vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4