[core/input] Move from select to epoll

Use epoll instead of select in order to be able to use level-triggered
semantics and not get stuck on the first event.

tests/modules/test_disk.py

@@ -7,7 +7,7 @@ import mock
 import bumblebee.input
 from bumblebee.input import I3BarInput
 from bumblebee.modules.disk import Module
-from tests.util import MockEngine, MockConfig, assertPopen, assertStateContains
+from tests.util import MockEngine, MockConfig, assertPopen, assertStateContains, MockEpoll
 
 class MockVFS(object):
     def __init__(self, perc):
@@ -24,7 +24,7 @@ class TestDiskModule(unittest.TestCase):
         self.config.set("disk.path", "somepath")
         self.module = Module(engine=self.engine, config={"config": self.config})
 
-    @mock.patch("select.select")
+    @mock.patch("select.epoll")
     @mock.patch("subprocess.Popen")
     @mock.patch("sys.stdin")
     def test_leftclick(self, mock_input, mock_output, mock_select):
@@ -33,7 +33,7 @@ class TestDiskModule(unittest.TestCase):
             "button": bumblebee.input.LEFT_MOUSE,
             "instance": None
         })
-        mock_select.return_value = (1,2,3)
+        mock_select.return_value = MockEpoll()
         self.engine.input.start()
         self.engine.input.stop()
         mock_input.readline.assert_any_call()