Added Optimizely script tag.

Closes gh-1629.
Bug #855940 - Update newrelic to v0.9.20
Bug #3375 - Switch to html5-lint npm module
jade patch to undo multiply-sanitized html entities
[#3260] Submodule update for soundcloud fix
Butter v1.0.25
Bug #2945
1. Stop the draggable update timeout if the track event which was originally dragged is deleted.
2. Call __onDraggableMouseUp manually due to Chrome bug.
3, Fixed bug in removal of mouseup listeners for draggable elements.
[#3451] Properly play again if media with greater duration added while playing
Merge branch 'master' of github.com:mozilla/butter
Bug #856501 - Move webmakernav styles into butter.ui.less
No Bug - Re-enable linting of LESS files
[2646] We need an internal facing index of created projects
[t3252] code formatting
[t3437] Inputs with the percent unit box not displaying properly (Opera 12.14; OSX, Ubuntu, Mint)
Merge branch 'master' of github.com:mozilla/butter
ignore it