Revert "Replace deprecated pre-C++11 code (#1890)"

This reverts commit 597672a.

Author: peternewman

common/utils/StringUtils.cpp

@@ -454,12 +454,12 @@ bool HexStringToInt(const string &value, int64_t *output) {
 
 void ToLower(string *s) {
   std::transform(s->begin(), s->end(), s->begin(),
-                 [](int value){return std::tolower(value);});
+                 std::ptr_fun<int, int>(std::tolower));
 }
 
 void ToUpper(string *s) {
   std::transform(s->begin(), s->end(), s->begin(),
-                 [](int value){return std::toupper(value);});
+                 std::ptr_fun<int, int>(std::toupper));
 }
 
 void CapitalizeLabel(string *s) {

include/ola/ExportMap.h

@@ -77,7 +77,8 @@ class BaseVariable {
   std::string m_name;
 };
 
-struct VariableLessThan {
+struct VariableLessThan: public std::binary_function<BaseVariable*,
+                                                     BaseVariable*, bool> {
   bool operator()(BaseVariable *x, BaseVariable *y) {
     return x->Name() < y->Name();
   }

include/olad/Plugin.h

@@ -107,7 +107,8 @@ class AbstractPlugin {
 };
 
 
-struct PluginLessThan {
+struct PluginLessThan: public std::binary_function<AbstractPlugin*,
+                                                   AbstractPlugin*, bool> {
   bool operator()(AbstractPlugin *x, AbstractPlugin *y) {
     return x->Id() < y->Id();
   }