Change naming convention for wrapped ctors and dtor

Use Foo_{new,delete}() instead of {new,delete}_Foo() to ensure that all
methods of the class Foo start with the corresponding prefix.

Examples/test-suite/c/cpp_basic_class_method_runme.c

@@ -3,11 +3,11 @@
 
 int main(int argc, const char *argv[])
 {
-    MyClass *mc = new_MyClass();
+    MyClass *mc = MyClass_new();
 
     assert(MyClass_someMethod(mc) == 42);
 
-    delete_MyClass(mc);
+    MyClass_delete(mc);
 
     return 0;
 }