[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/core/input.py

@@ -0,0 +1,69 @@
+import uuid
+import logging
+
+import core.event
+
+import util.cli
+
+LEFT_MOUSE = 1
+MIDDLE_MOUSE = 2
+RIGHT_MOUSE = 3
+WHEEL_UP = 4
+WHEEL_DOWN = 5
+
+
+def button_name(button):
+    if button == LEFT_MOUSE:
+        return "left-mouse"
+    if button == RIGHT_MOUSE:
+        return "right-mouse"
+    if button == MIDDLE_MOUSE:
+        return "middle-mouse"
+    if button == WHEEL_UP:
+        return "wheel-up"
+    if button == WHEEL_DOWN:
+        return "wheel-down"
+    return "n/a"
+
+
+class Object(object):
+    def __init__(self):
+        super(Object, self).__init__()
+        self.id = str(uuid.uuid4())
+
+
+def __event_id(obj_id, button):
+    return "{}::{}".format(obj_id, button_name(button))
+
+
+def __execute(cmd):
+    try:
+        util.cli.execute(cmd, wait=False)
+    except Exception as e:
+        logging.error("failed to invoke callback: {}".format(e))
+
+
+def register(obj, button=None, cmd=None):
+    event_id = __event_id(obj.id if obj is not None else "", button)
+    logging.debug("registering callback {}".format(event_id))
+    if callable(cmd):
+        core.event.register(event_id, cmd)
+    else:
+        core.event.register(event_id, lambda _: __execute(cmd))
+
+
+def trigger(event):
+    if not "button" in event:
+        return
+
+    triggered = False
+    for field in ["instance", "name"]:
+        if not field in event:
+            continue
+        if core.event.trigger(__event_id(event[field], event["button"]), event):
+            triggered = True
+    if not triggered:
+        core.event.trigger(__event_id("", event["button"]), event)
+
+
+# vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4