title: detect Developer Setting 'do not keep activities'
body: <p>How can I detect if a device has 'do not keep activities' set in developer options.
  I can't find this value in the settings-class.</p>
  
  <p>I need this setting to know, because when 'do not keep activities' is activated my app gets problem with it. 
  Example : I have a main-activity and a sub-activity. when I switch from main to sub and back from sub to main, then the main-activity will be started again. This is because the mainactivity was killed before. besause I do a lot of loading in my main-activity, the app is not usable when starting over and over.</p>
  
  <p>Or is there any method to solve this problem ?
  Without this setting activated, there is no problem.</p>
  
  <p>regards</p>