Use import instead of destructuring

This is a followup to 0ffc2c0c96542c5aa8766dbd79d2b7f1dbfc481a. By using import we get static error checking which found some minor bugs.

Review URL: https://github.com/google/traceur-compiler/pull/430

Closes #430.
Fix syntax error on Safari 5.1.

Old versions of Safari did not support string names for accessors.
For example the following did not work:

```js
var obj = {
  get "foo"() {}
}
```

Closes #417
Closes #434
Publish demos on gh-pages, fixes #220

Add index.html that redirects to wiki GettingStarted.
Add make target wiki and wikiclean, to refresh compiled content.
Add greeter compiled content to test site.

Review URL: https://github.com/google/traceur-compiler/pull/418

Closes #418.