disabled fetching summary if fetch error before
sources.yml: introduced domain to reduce copy and paste for lang, copyright and domain address
cosmetics for printing debug in NewsManager
NewsList: do not end toString with newline
moving from YAML::Syck to YAML::Any
extracted PolishWikinewsSummaryExtractor, moved MAX_SUMMARY_LEN to Settings.pm
NewsHeadline: read news summary using API and YAML
extracted NewsListReader from NewsSource
refresh only if feed saved before, vulgar logic in manager
cosmetic in OldHtmlPageReader
introduced ApiHtmlPageReader and MediaWikiApi.pm