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.

Compile wiki files on test Makefile target