Bug 1036517 - Remove old location uploading code. r=blassey

I kept the existing preference UI since the new stumbler implementation
intends to use it.  I kept the pref listener since Bug 1036508 may elect
to keep using the existing Gecko pref.
Bug 1032217 - Export gecko.{WebApp,BrowserApp}. r=bnicholson

This allows explicit intents from outside of the App.  Tested locally by:

* creating and launching a home screen shortcut; (the presenting issue)

* trying a an "old style" webapp home screen launch, like:

adb shell am start -a org.mozilla.gecko.WEBAPP -n org.mozilla.fennec_nalexander/.Webapp -d http://penguinpop.justplaymobile.com/penguinpop.webapp

and

adb shell am start -a org.mozilla.gecko.WEBAPP -n org.mozilla.fennec_nalexander/org.mozilla.gecko.Webapp -d http://penguinpop.justplaymobile.com/penguinpop.webapp

Both log the expected message in the dispatcher:

W GeckoWebappImpl(12501)      no package name; treating as legacy shortcut

Both fail with:

E GeckoConsole(12177)         Error getting pref for application/x-web-app-manifest+json.

I verified that this behaviour happens with the Nightly of June 24, 2014 -- the
one right before the patch that introduced this regression.