Fix crash of nearby list when the places list is null

[tobias47n9e]

Currently the NearbyController crashes when it is called with a
places list that is null. This is caused by the NearbyMapFragment
not handling this state correctly.
This commit adds tests for an empty list and null, which reproduce
the problem. An early return in the NearbyController can make
the tests pass, but might not be the best solution for this issue.

[tobias47n9e]

Related but maybe not best solution for #672

The fix causes the map to have no markers, if the places list happens to be null.

[misaochan]

The Travis build fails due to failing tests. Are these the same tests that you wrote?

[tobias47n9e]

It says:

fr.free.nrw.commons.SettingsActivityTest > 
afterClickingCcby4ItWillStay[test(AVD) - 5.1.1] FAILED 

android.support.test.espresso.NoMatchingViewException: No views in hierarchy found 
matching: (is descendant of a: with id: fr.free.nrw.commons:id/settingsFragment and 
with res-name that is "list" and has focus on the screen to the user)

f the target view is not part of the view hierarchy, you may need to use Espresso.onData 
to load it from one of the following AdapterViews:android.widget.ListView{263b671c 
VFED.VC. ......I. 0,0-480,678 #102000a android:id/list}

:app:connectedDebugAndroidTest FAILED

FAILURE: Build failed with an exception.

The test passes locally. Will see if rerunning travis will help once again.

[tobias47n9e]

I passed the tests now. I will still deal with the codacy checks.