Implement fix from https://bugzilla.redhat.com/show_bug.cgi?id=1006063#c2, item: I, II

Fix on item I and II

I. Since the filter "Has Warning" now includes error as well, 
  please change the label to "Invalid" with tooltip that says "Translation that does not pass the validator, includes warning and error."

II. When you make an invalid error and click somewhere else, 
    click on "return to editor" should make the input focus back to the confronting translation. 

 Step to reproduce:
 1. Set the validation level to Error on "printf"
 2. Go to any document, click on translation entry for row 2.
 3. Trigger the validation error, 
    such as type excess "%d", DO NOT save now.
 4. Click on translation entry of row 2.
 5. In the "You're trying to save translation that contains validation error",
    Click "Return to editor"

 Expected:
   Input focus is back to row 1. 

 Actual:
   Input focus stays on row 2.