config: add gevent dependency and min_threads option

- requirements.txt: add gevent for cooperative concurrency
- config.py: add min_threads setting for thread scaling

config.py

@@ -86,6 +86,7 @@ class Config(ComboParser):
         self.add_item(section, 'outage_threshold', float, 4.0, 'mininum success percentage required to not drop check results', False)
         self.add_item(section, 'max_fail', int, 5, 'number of fails after which a proxy is considered dead', False)
         self.add_item(section, 'threads', int, 10, 'number of threads watchd uses to check proxies', True)
+        self.add_item(section, 'min_threads', int, 0, 'minimum threads (0 = auto: threads/4)', False)
         self.add_item(section, 'timeout', int, 15, 'timeout for blocking operations (connect/recv/...) for proxy checks in seconds', False)
         self.add_item(section, 'submit_after', int, 200, 'min. number of tested proxies for DB write', False)
         self.add_item(section, 'debug', bool, False, 'whether to print additional debug info', False)

requirements.txt

@@ -1,3 +1,4 @@
 beautifulsoup4
 pyasn
-IP2Location
+IP2Location
+gevent