fix(change_detection/lexer): support production mode

The Lexer uses the global `assert` function of Dart, which is not
yet available in JavaScript. Later on, all `assert` statements should
be automatically removed by Traceur.
feat(compiler): add benchmarks

- compileEmptyTemplate
- compile25ElementsNoBindings
- compile25ElementsWithBindings

For the results see the PR #197.

Closes #197