Java/C# std::vector<bool> workarounds for clang

Workaround clang++ 9.1.0 error not knowing std::vector<bool>::const_reference
is actually typedef to bool:

  li_std_vector_wrap.cxx:1838:40: error: no matching constructor for initialization of 'std::vector<bool>::const_reference'

Workaround is use

  const value_type& getitem(int index) throw (std::out_of_range) { ...
  // bool specialization:
  bool getitem(int index) throw (std::out_of_range) { ...

instead of

  const_reference_type getitem(int index) throw (std::out_of_range) { ...

Although the following would be better, it would require a more
complicated implementation:

  const_reference_type getitem(int index) throw (std::out_of_range) { ...
  // bool specialization:
  bool getitem(int index) throw (std::out_of_range) { ...

Lib/java/std_vector.i

@@ -129,7 +129,7 @@ SWIGINTERN jint SWIG_VectorSize(size_t size) {
         }
       }
 
-      const_reference doGet(jint index) throw (std::out_of_range) {
+      CONST_REFERENCE doGet(jint index) throw (std::out_of_range) {
         jint size = static_cast<jint>(self->size());
         if (index >= 0 && index < size)
           return (*self)[index];