FIX: install/update app with permissions on b2g instance

[rpl]

This change hooks the new remote webappsActor to install apps into a b2g instance
using mozApps internals, so application permissions will be registered and
correctly available.

This merge should fix: #237

[digitarald]

Hooray!

Only issue I run into when using the actor (from my own xpcshell script), was that re-installs didn't work as expected. Like adding/removing fullscreen or other properties from the manifest wasn't recognized until I uninstalled the app and rebooted the phone.

[rpl]

Currently I left intact the method we use to remove applications and I get a reasonable doubt that in this way some information (such as permissions that are registered and de-registered during the installation and uninstallation) will be left in the system.

I need to go a bit deeper (although in the end the real solution is surely to provide the opposite function into an debugger server actor)

[mykmelez]

Nit: this would be easier to read if the object argument was more structured:

remote.client.request({ to: remote.webapps,
                        type: "install",
                        appId: appId,
                        appType: appType },
                      onResponse);

That also makes the lines short enough to enable you to call request() directly on this._remote.client without exceeding 80 characters per line, so you don't have to assign it a local variable that then only gets used once:

this._remote.client.request({ to: remote.webapps,
                              type: "install",
                              appId: appId,
                              appType: appType },
                            onResponse);

[rpl]

I've introduced suggested code cleanup and fixed a regression (due to new app install method and b2g install forced kill)

In the last commit I've removed from tab worker message handler any simulator.kill used from the previous install/upgrade method.

I've not been yet able to study more deeply potential problems related to the cases mentioned by @digitarald

[mykmelez]

Thanks for the fixes!