Revert "feat(http): support coalescing http requests"

This reverts commit 1fb668b7f7154fd40a4112f2b24f455557ae740d.

Only reverting because g3 is not ready for it yet.
fix(cache): Make UnboundedCache extend Cache

Closes #1174
docs(developer): fix developer docs listing incorrect scripts to run for testing

DEVELOPER.md previously directed developers to run scrips/env.sh before running
tests, which is unnecessary and will cause their terminal to exit whenever
a command ends with a non-0 exit code.

Closes #1187
Closes #1188
docs(developer): fix typo in DEVELOPER.md

Closes #1210
fix(examples): do not use shadow DOM

This is in preparation for implementing the Testability API and Protractor
end-to-end tests since chromedriver can't handle shadowDom references.
fix(karma): remove saucelabs from default browser list.
feat(animate): animationsAllowed property to turn off all animations

This is required for writing end-to-end tests against AngularDart apps
that use animations.  In such tests, you typically want to test the
functionality of the application and not necessarily deal with the
animations.  This allows you to turn off all animations in your
production site under test.

The Animate class has a new property, animationsAllowed, which can be
set to false to disable all animations.  When true (the default),
whether or not animations occur depend on the animation module installed
and the AnimationOptimizer.