Removed Array.forEach usage to recover IE7/8 compatibility
exhibit-api.js load es5-shim.js to provide Array.forEach and other
more-recent js elements; however, exhibit-api.js was using forEach
*before* es5-shim.js was loaded, which broke IE7/8 compatibility.
Merge pull request #87 from karger/2014-03-24_forEach_IE7

Removed Array.forEach usage to recover IE7/8 compatibility