Merge branch 'gh-pages' of https://github.com/aalexandrov/stratosphere into rmetzger_preview

Conflicts:
	_config.yml
Merge branch 'gh-pages' of https://github.com/dimalabs/ozone into rmetzger_preview
first part
added lightboxes for the screenshots and data images
Merge remote-tracking branch 'origin/gh-pages' into rmetzger_preview

Conflicts:
	_config.yml
Merge branch 'demo' into rmetzger_preview
postdocs -> co-leads
Merge branch 'gh-pages' of https://github.com/stratosphere/stratosphere into gh-pages

Merge branch 'gh-pages' of https://github.com/stratosphere/stratosphere into gh-pages
Update example.markdown
rework downloads page, added FAQ entry and fixed GSOC blog post
some rewording
adressed Stephan's comments on GitHub
update yarn tgz dl link for snapshot & test new website hosting
Replaced unreliable gutenberg.org link by link to Apache license.
Adapted documentation according to developer comments
Fixes navbar bug
Merge pull request #2 from JonathanH5/cssfix

Fixes navbar bug
Merge pull request #1 from twalthr/BCVarsDocumentation

Adapted documentation according to developer comments
Added Event buzzworld and changed logo
Merge pull request #3 from JonathanH5/BandL

Added event Buzzworld and changed Logo in materials section