update test/harness_browser.html to use all the latest *.js scripts

- all tests passing in dartium and chrome
- removed a part.js artifact from dart2js
chrome.dart : remove extraneous imports, the exports do all necessary work

since this file does not need any of the imported types (there is no
code here) those imports do nothing; I think this makes the file a bit
easier on the eyes :)
Merge pull request #42 from rmsmith/master

update test/harness_browser.html to use all the latest *.js scripts