Update to 0.15.0

[Minzord]

Update to 0.15.0

Changelog:

* New engines
    Acgsou (files, images, videos, music)
    Duden.de (general)
    Seznam (general)
    Mojeek (general)

* New languages
    Catalan
    Welsh
    Basque
    Persian (Iran)
    Galician
    Dutch (Belgium)
    Telugu
    Vietnamese

* New random answerers
    sha256
    uuidv4

• New DOI resolsvers sci-hub.tw

  • Fix Vim mode on Firefox

  • Fix custom select in Oscar theme

  • Engine fixes (duckduckgo, google news, currency convert, gigablast, google scholar, wikidata image, etymonline, google videos, startpage, bing image)

  • Minor simple theme fixes

  • New Youtube icon in Oscar theme

  • Get DOI rewriters from settings.yml

  • Hide page buttons when infinite scrolling is enabled

  • Update user agent versions

  • Make Oscar style configurable

  • Make suspend times of errored engines configurable

[JimboJoe]

Closing as there's already #41 ongoing. Thanks anyway!