This reverts commit 4d177039.

Add match_language function in utils to match any user given
language code with a list of engine's supported languages.

Also add language_aliases dict on each engine to translate
standard language codes into the custom codes used by the engine.

Add languages supported by either all default general engines or 10 engines.

Also, fix fetch_languages.py so it can run on python3.

First page now starts with 0 offset,
rather than starting on the 30th result.

DuckDuckGo returns 30 results on each page.

and refactor method to make it testable without making requests

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

Following engines does not support "Last year":
 * Bing News
 * DeviantArt
 * DuckDuckGo
 * Yahoo
 * YouTube (noapi)

only works if both country and language are set

test_duckduckgo modified to reflect changes in duckduckgo's html