fix yacy-engine and add comments

using generic mediawiki engines

* add language support
* add image-support
* add basic-implementation for video, music and file handling
* refactore engine
* add comments

* bug: setting language_support to False result in no results

* writing general mediawiki-engine
* using this engine for wikipedia
* using this engine for uncyclopedia

update search engines and add comments to it

* add language-support
* decrease search-results/site to 5
* add comments

* add paging support
* make number_of_results changable
* make result calculation more clear
* add comments

* add language-support
* add comments
* little refactoring

* add language support
* remove not required code
* improve google-ad detection (no false detection anymore, I hope)
* other improvements

update and fix search engines

engine generate (Error: None), I don't know why

little fix for google images engine

[courgette_theme] add autocomplete theme

New theme courgette

Add tests for searx.engines.(dummy|github)

Cover searx.utils