[core] Refactor engine

This is going to be a bit more comprehensive than anticipated. In order
to cleanly refactor the core and the engine, basically start from
scratch with the implementation.

Goals:

* Test coverage
* Maintain backwards compatibility with module interface as much as
  possible (but still make modules easier to code)
* Simplicity

see #23

bumblebee/modules/pacman.py

@@ -1,58 +0,0 @@
-import bumblebee.module
-import subprocess
-import os
-
-def description():
-    return "Displays available updates per repository for pacman."
-
-class Module(bumblebee.module.Module):
-    def __init__(self, output, config):
-        super(Module, self).__init__(output, config)
-        self._count = 0
-
-    def widgets(self):
-        path = os.path.dirname(os.path.abspath(__file__))
-        if self._count == 0:
-            self._out = "?/?/?/?"
-            process = subprocess.Popen([ "{}/../../bin/customupdates".format(path) ], stdout=subprocess.PIPE, stderr=subprocess.PIPE)
-            
-            self._query, self._error = process.communicate()
-
-            if not process.returncode == 0:
-                self._out = "?/?/?/?"
-            else:
-                self._community = 0
-                self._core = 0
-                self._extra = 0
-                self._other = 0
-
-                for line in self._query.splitlines():
-                    if line.startswith(b'http'):
-                        if b"community" in line:
-                            self._community += 1
-                            continue
-                        if b"core" in line:
-                            self._core += 1;
-                            continue
-                        if b"extra" in line:
-                            self._extra += 1
-                            continue
-                        self._other += 1
-                self._out = str(self._core)+"/"+str(self._extra)+"/"+str(self._community)+"/"+str(self._other)
-            
-        self._count += 1
-        self._count = 0 if self._count > 300 else self._count
-        return bumblebee.output.Widget(self, "{}".format(self._out))
-
-    def sumUpdates(self):
-        return self._core + self._community + self._extra + self._other 
-    
-    def critical(self, widget):
-        #return self._sumUpdates(self)
-        return self.sumUpdates() > 0
-
-
-
-
-
-# vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4