fix youtube engine and add comments

## Youtube (Videos)

# 

# @website     https://www.youtube.com/

# @provide-api yes (http://gdata-samples-youtube-search-py.appspot.com/)

# 

# @using-api   yes

# @results     JSON

# @stable      yes

# @parse       url, title, content, publishedDate, thumbnail

from json import loads

from urllib import urlencode

from dateutil import parser

# engine dependent config

categories = ['videos']

search_url = ('https://gdata.youtube.com/feeds/api/videos'

              '?alt=json&{query}&start-index={index}&max-results=25')  # noqa

paging = True

language_support = True

# search-url

base_url = 'https://gdata.youtube.com/feeds/api/videos'

search_url = base_url + '?alt=json&{query}&start-index={index}&max-results=5'  # noqa

# do search-request

def request(query, params):

    index = (params['pageno'] - 1) * 25 + 1

    index = (params['pageno'] - 1) * 5 + 1

    params['url'] = search_url.format(query=urlencode({'q': query}),

                                      index=index)

    # add language tag if specified

    if params['language'] != 'all':

        params['url'] += '&lr=' + params['language'].split('_')[0]

    return params

# get response from search-request

def response(resp):

    results = []

    search_results = loads(resp.text)

    # return empty array if there are no results

    if not 'feed' in search_results:

        return results

        return []

    feed = search_results['feed']

    # parse results

    for result in feed['entry']:

        url = [x['href'] for x in result['link'] if x['type'] == 'text/html']

        if not url:

            return

        # remove tracking

        url = url[0].replace('feature=youtube_gdata', '')

        if url.endswith('&'):

            url = url[:-1]

        title = result['title']['$t']

        content = ''

        thumbnail = ''

#"2013-12-31T15:22:51.000Z"

        pubdate = result['published']['$t']

        publishedDate = parser.parse(pubdate)

        else:

            content = result['content']['$t']

        # append result

        results.append({'url': url,

                        'title': title,

                        'content': content,

                        'publishedDate': publishedDate,

                        'thumbnail': thumbnail})

    # return results

    return results

  - name : youtube

    engine : youtube

    categories : videos

    shortcut : yt

  - name : dailymotion

    engine : dailymotion

    locale : en_US

    categories : videos

    shortcut : dm

  - name : vimeo