Solved item 54

54) add a API check to omniauth.rb
    check that all array constants are initialized for all login providers
Solved item 16

16) find optimal image format for each provider. For API_OG_DEF_IMAGE hash
    http://sproutsocial.com/insights/social-media-image-sizes-guide
    https://docs.google.com/spreadsheets/d/1IpTYTTMJLcSXcPDtW9zSbPBHQyRdrLfKERohGIIkE_Q/edit