Bug 1058160 - Make o.m.g.BrowserApp LAUNCHER activity default and high priority. r=bnicholson

In order to launch in response to the MAIN activity (via |adb shell am
start -a android.intent.action.MAIN org.mozilla.fennec|, for example),
the activity must have category default.  That is added automatically to
<activity> elements that have category LAUNCHER, but apparently not to
<activity-alias> elements.  This patch adds it manually.

In general, <intent-filters> are prioritized by their order in the
manifest file.  To avoid future confusion, this patch bumps the
android:priority of the existing filter.

--HG--
extra : rebase_source : 021da06af2f3e41fc0f38eee7fc33360797f64b0
Bug 1057637 - Extract a re-usable ExpandableListAdapter out of RemoteTabsList. r=mcomella

This patch does a few other small things as well:

* It exposes the client device type.  This will be used later, as part of
  the visual refresh.
* Aligns the field names in remote_tabs_child with the names used by
  TwoLinePageRow.  This will be used later, when we finally use said
  standard view class.

--HG--
extra : rebase_source : 291f69a5f9b68801dd9154c5d291c6795d218ff6