Revert "DOM: Converted from strtol to std::stoi"

This reverts commit 7c5055de7a.

src/DOM.cpp

@@ -337,7 +337,7 @@ bool DOM::get (const std::string& name, const Task& task, Variant& value)
     std::map <std::string, std::string> annos;
     ref.getAnnotations (annos);
 
-    int a = std::stoi (elements[1]);
+    int a = strtol (elements[1].c_str (), NULL, 10);
     int count = 0;
 
     // Count off the 'a'th annotation.