Don't show the menu in MainActivity for now
Add uses-permission INTERNET to manifest
Add retrofit as gradle dependency
Create api.Photo POJO class
Add first test with retrofit
Convert MainActivity to spaces
Add id textView in activity_main.xml
Merge branch 'feature/retrofit' into develop

* feature/retrofit:
  Add id textView in activity_main.xml
  Convert MainActivity to spaces
  Add first test with retrofit
  Create api.Photo POJO class
  Add retrofit as gradle dependency