[core] Rework core implementation

Experimental re-implementation of core functionality with the aim:
- Depend only on the Python Standard Library for core
- If modules are missing elsewhere, *never* throw
- Unit test *everything*
- Cleaner and more minimal implementation
- Better integration points for existing implementations (charts,
  braille, etc.)
- Full backwards-compatibility with existing module system (except where
  modules can be vastly simplified)

bumblebee-status

@@ -1,80 +1,21 @@
 #!/usr/bin/env python
 
-import os
 import sys
-import logging
-import signal
-import bumblebee.theme
-import bumblebee.engine
-import bumblebee.config
-import bumblebee.output
-import bumblebee.input
-import bumblebee.modules.error
-
-try:
-    reload(sys)
-    sys.setdefaultencoding('UTF8')
-except Exception:
-    pass
-
+import core.output
 
 def main():
-    def sig_USR1_handler(signum,stack):
-        engine.write_output()
+    output = core.output.i3()
+    modules = []
+#    modules = core.module.modules()
+    sys.stdout.write(output.start())
+    while True:
+        sys.stdout.write(output.begin_status_line())
+        for module in modules:
+#            module.update()
+            sys.stdout.write(output.draw(module))
+        sys.stdout.write(output.end_status_line())
+    sys.stdout.write(output.stop())
         
-    config = bumblebee.config.Config(sys.argv[1:])
-
-    if config.debug():
-        if config.logfile() in ["stdout", "stderr"]:
-            logging.basicConfig(
-                level=logging.DEBUG,
-                format="[%(asctime)s] %(levelname)-8s %(message)s",
-                stream=sys.stdout if config.logfile() == "stdout" else sys.stderr
-            )
-        else:
-            logging.basicConfig(
-                level=logging.DEBUG,
-                format="[%(asctime)s] %(levelname)-8s %(message)s",
-                filename=config.logfile()
-            )
-
-    theme = bumblebee.theme.Theme(config.theme(), config.iconset())
-    output = bumblebee.output.I3BarOutput(theme=theme, config=config)
-    inp = bumblebee.input.I3BarInput()
-    engine = None
-
-    try:
-        engine = bumblebee.engine.Engine(
-            config=config,
-            output=output,
-            inp=inp,
-            theme=theme,
-        )
-        signal.signal(10,sig_USR1_handler)
-        engine.run()
-    except KeyboardInterrupt as error:
-        inp.stop()
-        sys.exit(0)
-    except BaseException as e:
-        if not engine: raise
-        module = engine.current_module()
-        logging.exception(e)
-        if output.started():
-            output.flush()
-            output.end()
-        else:
-            output.start()
-        import time
-        while True:
-            output.begin()
-            error = bumblebee.modules.error.Module(engine, config)
-            error.set("exception occurred: {} in {}".format(e, module))
-            widget = error.widgets()[0]
-            widget.link_module(error)
-            output.draw(widget, error)
-            output.flush()
-            output.end()
-            time.sleep(1)
 
 if __name__ == "__main__":
     main()