merge app before dummy/app

merging the app first allows common files in the dummy/app to overwrite
the files in the addon's app dir. This is how EmberCLI handles addon
file conflicts.
rename ember-addon-main file to the project name
the app and router should be from the dummy/app
use the assets/test-support files
simple test confirmation hello-adodn

simple initial tests to confirms the addon is working in the consuming app.
moved dummy-app to dummy/app
environment config for dummy/app