Remove retrolambda from project, to add Play services.

Play services are required to show map.
Show a map on location list item tap.
Show locations on map
Add Play services on Travis and change Play minimum version for Travis
Fixes for Travis.

Undefine Play services version, so latest found will be used.
Remove unused library from .travis.yml.
Revert Play services version for Travis
Merge branch 'feature/add-locations-map' into develop
Fix merge conflicts