Update enum type to use strings

Author: Caitlin Bales (MSFT)

Templates/PHP/Model/EnumType.php.tt

@@ -23,7 +23,7 @@ class <#=enumT.Name.ToUpperFirstChar()#> extends Enum
     int count = 0;
     foreach(var value in enumT.Members)
     {
-        count++;
+        
 		var needsPrefix = TypeHelperPHP.ReservedNames.Contains(value.Name.ToUnderscore());
 
 		if (needsPrefix)
@@ -33,8 +33,9 @@ class <#=enumT.Name.ToUpperFirstChar()#> extends Enum
 <#
 		} else {
 #>
-    const <#= value.Name.ToUnderscore().ToUpper()#> = <#= count#>;
+    const <#= value.Name.ToUnderscore().ToUpper()#> = "<#= count#>";
 <#		}
+	count++;
     }
 #>
 }