refactor(benchmark): simplify writing benchmarks

Adds `benchmarks/benchpress` module and adjusts the compiler
benchmarks to use it. Also adds the Angular 1.3 benchmark
to the compiler benchmarks.

Closes #202
feat(ChangeDetector): implement enabling/disabling records
refactor(ElementInjector): remove stale file and make StaticKeys private
fix(compiler): use parentheses around expressions and escape quotes
fix(test_lib): allow equality tests for `Map`
feat(Change Detection): Child watch groups
feat(ChangeDetector): change View to construct a WatchGroup hierarchy
feat(bootstraping): application bootstrapping implementation.

Entry-point to bootstrapping is a rootComponent. The bootstrapping
method, uses the component's selector to find the insertion element in
the DOM, and attaches the component in its ShadowRoot.
feat(examples): adds hello-world app.

The app is writen in ES6 and transpiles to ES5 and dart as part of the
usual build.

The app contains a component, a directive and a services wired together
through dependency injection.

Before Each:
- gulp build

For es5:
- gulp serve
- open 'localhost:8000/js/examples/lib/hello_world/'

For dart:
- gulp examples/pub.serve
- open 'localhost:8080'
fix(class fields): handle untyped fields
feat(compiler): new semantics for `template` attributes and view variables.

- Supports `<div template=“…”>`, including parsing the expressions within
  the attribute.
- Supports `<template let-ng-repeat=“rows”>`
- Adds attribute interpolation (was missing previously)
feat(compiler): support `on-` and `[]`
fix(build): don’t do `pub get` until all pub specs have been copied

Fixes #130
Closes #227
feat(ChangeDetector): implement enabling/disabling watch group
refactor(ChangeDetector): rename WatchGroup into RecordRange
doc(example): adds comments to the hello world app.

Explains the basic concepts as seen in the demo app, but it is not a
substitute for proper documentation which will come later.
doc(readme): adds examples to readme.
fix(examples): hello-world app on Windows
feat(ChangeDetection): convert Record.mode to a bit field
feat(RecordRange): Set context for implicit receivers only