Use the new build env on Travis

more ram, more cpu, better boot times, caching built in
palette style changes
restrict marshalling depth only for nativeGetCallback
resizeGutter_fix private
remove Chrome glow with outline-style:none
remove contenteditable from codeTextbox
remove typeFuncs and typeHint
rake task to dump script cache to redis, attempt to get script cache from redis before the db
add to build script, explicitly eager load the Script's db connection if Marshal fails because its stuff isn't loaded
make the nonsense less nonsense
Dropbox and Gsheet changes
don't write to s3 when unit testing
Merge branch 'staging' of github.com:code-dot-org/code-dot-org into staging
Non-modified images need an expiry
Merge branch 'test' of github.com:code-dot-org/code-dot-org into staging
reduce writes for logged in users
no update if not updating
hey tests, I broke that on purpose
remove useless nil check
Merge pull request #832 from code-dot-org/l2-redis

use redis as an L2 cache for the Script.script_cache stuff