changed links for testing

Changed links for testing; actual URLs may differ in final version.

another link update

Updated header logo

shrunk logo down

Second group of fixes for landing page integration.

Second set of landing page integration changes.

fixed footer link to read 'survey'.

Removed superfluous base page; used blocks to remove small logo from main page; recompiled scss per line comment.
Merge branch 'doc'
Clean-up formatting and remove commented code.
Fix menu highlight for home page.
Merge branch 'master' of https://github.com/codalab/codalab into dev