Use CallStack printer instead

This makes a flamegraph like colored call stack with percentages for
each method call. It's much easier to see where the time is being spent
than by using a text printer or graph printer.

Author: eileencodes

graphs/rails4.2_controller_create_callstack.html

@@ -6,7 +6,7 @@ class DocumentsControllerTest < ActionController::TestCase
       get :index
       assert_equal 200, response.status
     end
-    printer = RubyProf::GraphHtmlPrinter.new(result)
+    printer = RubyProf::CallStackPrinter.new(result)
     printer.print(STDOUT, {})
   end
 
@@ -25,7 +25,7 @@ class DocumentsControllerTest < ActionController::TestCase
       assert_equal 'New things', document.title
       assert_equal 'Doing them', document.content
     end
-    printer = RubyProf::GraphHtmlPrinter.new(result)
+    printer = RubyProf::CallStackPrinter.new(result)
     printer.print(STDOUT, {})
   end
 

graphs/rails4.2_controller_create_flamegraph.html

@@ -7,7 +7,7 @@ class DocumentsIntegrationTest < ActionDispatch::IntegrationTest
       get '/documents'
       assert_equal 200, response.status
     end
-    printer = RubyProf::GraphHtmlPrinter.new(result)
+    printer = RubyProf::CallStackPrinter.new(result)
     printer.print(STDOUT, {})
   end
 
@@ -26,7 +26,7 @@ class DocumentsIntegrationTest < ActionDispatch::IntegrationTest
       assert_equal 'New things', document.title
       assert_equal 'Doing them', document.content
     end
-    printer = RubyProf::GraphHtmlPrinter.new(result)
+    printer = RubyProf::CallStackPrinter.new(result)
     printer.print(STDOUT, {})
   end