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/c/exception/runme.c

@@ -7,7 +7,7 @@
 #include "example_wrap.h"
 
 int main() {
-  Test *t = new_Test();
+  Test *t = Test_new();
 
   SWIG_try {
     Test_unknown(t);