complete greek translation

[averello]

• translate all remaining entries
• remove fuzzy translations
• modify some entries with terms from the Hellenic National Meteorological Service http://www.hnms.gr/hnms/greek/meteorology/full_story_html?dr_url=/docs/lexikon/lexicon&dr_page_number=1

Signed-off-by: George Boumis developer.george.boumis@gmail.com