removed executable bit on web/static content
crushed pngs
[ak] Fix startPage to be start-page

BUG=

Review URL: https://codereview.chromium.org//170803002
dartdoc-viewer should not ship a static sitemap

R=alanknight@google.com

Review URL: https://codereview.chromium.org//170033002
docs: omit redirect script from app.yaml and rename to AngularDart