update changelog and version.py

0.15.0 2019.01.06

=================

- 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

0.14.0 2018.02.19

=================

# version of searx

VERSION_MAJOR = 0

VERSION_MINOR = 14

VERSION_MINOR = 15

VERSION_BUILD = 0

VERSION_STRING = "{0}.{1}.{2}".format(VERSION_MAJOR,