Rename README and DESIGN so their markdown gets picked up my GitHub.

BUG=skia:
R=mtklein@google.com

Author: jcgregorio@google.com

Review URL: https://codereview.chromium.org/231883008

git-svn-id: http://skia.googlecode.com/svn/trunk@14130 2bbb7eff-a529-9590-31e7-b0007b416f81
2 files changed