This change installs HttpModule with ServerModule, and overrides bindings to
service Http requests made from the server with the 'xhr2' NPM package.
Outgoing requests are wrapped in a Zone macro-task, so they will be tracked
within the Angular zone and cause the isStable API to show 'false' until they
return. This is essential for Universal support of server-side HTTP.
Alex Rickabaugh
Victor Berchet
Igor Minar
Miško Hevery
Alex Eagle
Joost de Vries