Fix missing top-left logo on some of the pages.
Merge pull request #468 from cpoulain/master

Fix missing top-left logo on some of the pages.
Reduce image size by an order of magnitude.
Remove unused JS scripts and load editor script only for the competition edit page.
Merge pull request #469 from cpoulain/master

Reduce image size and clean-up scripts in base template.
Merge branch 'master' of https://github.com/codalab/codalab into dev