[modules/pulsectl] add preliminary version of event-based pulseaudio

add a new module based on pulsectl, with pulsein for microphone and
pulseout for speakers.

should eventually become a drop-in replacement for pasink and pasource.

see #917

bumblebee_status/modules/core/pulseout.py

@@ -0,0 +1,9 @@
+from .pulsectl import Module
+
+
+class Module(Module):
+    def __init__(self, config, theme):
+        super().__init__(config, theme, "sink")
+
+
+# vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4