[mod] fetch supported languages for several engines

utils/fetch_languages.py gets languages supported by each engine and
generates engines_languages.json with each engine's supported language.

searx/engines/__init__.py

@@ -20,6 +20,7 @@ from os.path import realpath, dirname
 import sys
 from flask_babel import gettext
 from operator import itemgetter
+from json import loads
 from searx import settings
 from searx import logger
 from searx.utils import load_module
@@ -78,6 +79,9 @@ def load_engine(engine_data):
         if not hasattr(engine, arg_name):
             setattr(engine, arg_name, arg_value)
 
+    if engine_data['name'] in languages:
+        setattr(engine, 'supported_languages', languages[engine_data['name']])
+
     # checking required variables
     for engine_attr in dir(engine):
         if engine_attr.startswith('_'):
@@ -207,6 +211,8 @@ if 'engines' not in settings or not settings['engines']:
     logger.error('No engines found. Edit your settings.yml')
     exit(2)
 
+languages = loads(open(engine_dir + '/../data/engines_languages.json').read())
+
 for engine_data in settings['engines']:
     engine = load_engine(engine_data)
     if engine is not None: