When running in Dartium without using transformers (i.e. with a normal
static web server), handle relative template URLs. This works by using
mirrors to get the URL of the library where the component class is
defined.
Closes#2771Closes#3743
BREAKING CHANGE:
This change moves the http module into angular2/, so its import
path is now angular2/http instead of http/http.
Many other modules have also been moved around inside of angular2,
but the public API paths have not changed as of this commit.