get_from_cache uses string compares, multiple_games? uses script_levels, present_level populates @game_script_levels properly for old scripts
temporarily disable xsrf protection to prevent errors during load tests.
Merge branch 'staging' of github.com:code-dot-org/code-dot-org into staging
Merge pull request #766 from code-dot-org/cache-frozen-script

Ensure 20-hour script is cached fully for anonymous users (and fix flappy caching too)
Merge branch 'staging' of github.com:code-dot-org/code-dot-org into staging
Merge pull request #767 from code-dot-org/staging

DTT