Add log level config option

* Log levels can now be set via the command line and the configuration
  file.
* ServerConfig.load() function takes a file-like object now, rather than
  a string

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

tools/markov_import.py

@@ -23,7 +23,8 @@ async def main():
     channel = sys.argv[1]
     files = sys.argv[2:]
     server_config = ServerConfig()
-    server_config.load("config.toml")
+    with open("config.toml") as fp:
+        server_config.load(fp)
     # This only works on one plugin per config
     bot = Bot(server_config)
     plugin = [plugin for plugin in bot.plugins if isinstance(plugin, Markov)][0]