Improve --godeps mode to include all updates.

Without overriding IsContained, many updated packages were reported as
"  -" because contained uses the real local branch instead of the fake
fixed local revision.
Fix unbalanced tags in template, remove commented out code.

Add TODO item related to "installed_updates" div not being available
before all updates finish loading.
For unknown changes, display local and remote revisions.
Work on porting frontend JavaScript code to Go.
Fix script.go having non-main package.

That resulted in main() not being executed. See gopherjs/gopherjs#75
and go-on/gopherjslib#3 for relevant context.
Remove unnecessary //gopherjs:blocking comment.
Add js build tag.