Translation: /fundamentals/performance/index.markdown
Merge branch 'master' of https://github.com/google/WebFundamentals

Conflicts:
	.gitignore
	src/site/_config-devsite.yml
	src/site/_config.yml
	src/site/_contributors.yaml
translated performane/critical-rendering-path/index.markdown
fix typo in config files and delete trash file
rename performance/performance/critical-rendering-path -> performance/critical-rendering-path
revert .gitignore to previous version git
Merge pull request #867 from agektmr/discovery_and_distribution

fixing og:image url for social site sharing
Merge pull request #866 from CoderK/master

Translated "/fundamentals/performance/index.markdown" and "/fundamentals/performane/critical-rendering-path/index.markdown" into Korean.
Fix issue #870
Merge pull request #871 from jacquerie/issue-870

Fix issue #870
article "Optimizing URL Structure for Multi-Device Sites"