[tutorial] Chap 5: add URL to generic http.get() call

An Http.get() will always have at least a URL parameter.
minor code formatting fixes
Some dart code cleanup
refactor the demo

it works !
sync the html and the code
Use ng-cloak to hide "{{ ... }}" while loading

Fixes #11
Update the generated JS
integrate @chalin feedback
cleanup html
Update route DSL
Clarify the route config
ng-cloak
Merge pull request #7 from vicb/dart

Some dart code cleanup
Merge pull request #40 from chalin/patch-0227-chap5-http-get

[tutorial] Chap 5: add URL to generic http.get() call
Merge pull request #41 from vicb/patch-5

minor code formatting fixes
Add caveat to tutorial
improve code lab link