Changes to use common DirectorException class

Add director.swg for Go as was completely absent.
This is just the start of a common exception handling approach to directors.
An exception thrown in a Java director method will be propogated back to
Java via a C++ DirectorException.
DirectorException throws typemap for Java is fully working, all other languages need work.
DirectorException throws typemap for Perl added just to fix compilation errors.
Add director_exception_catches test.

Lib/go/director.swg

@@ -0,0 +1,15 @@
+/* -----------------------------------------------------------------------------
+ * director.swg
+ *
+ * This file contains support for director classes so that Go proxy
+ * methods can be called from C++.
+ * ----------------------------------------------------------------------------- */
+
+#include <exception>
+
+namespace Swig {
+
+  class DirectorException : public std::exception {
+  };
+}
+

Lib/java/java.swg

@@ -1051,6 +1051,10 @@ Swig::LocalRefGuard $1_refguard(jenv, $input); }
 %{ SWIG_JavaThrowException(jenv, SWIG_JavaRuntimeException, $1);
    return $null; %}
 
+// For directors to raise/throw the original Java exception
+%typemap(throws) Swig::DirectorException
+%{  $1.raiseJavaException(jenv);
+    return $null; %}
 
 /* Typemaps for code generation in proxy classes and Java type wrapper classes */
 

Lib/octave/director.swg

@@ -46,7 +46,22 @@ namespace Swig {
     }
   };
 
-  struct DirectorTypeMismatchException {
+  // Base class for director exceptions.
+  class DirectorException : public std::exception {
+  public:
+    static void raise(const char *msg) {
+      // ... todo
+      throw(DirectorException());
+    }
+
+    static void raise(const octave_value &ov, const char *msg) {
+      // ... todo
+      raise(msg);
+    }
+  };
+
+  class DirectorTypeMismatchException : public DirectorException {
+  public:
     static void raise(const char *msg) {
       // ... todo
       throw(DirectorTypeMismatchException());
@@ -58,7 +73,8 @@ namespace Swig {
     }
   };
 
-  struct DirectorPureVirtualException {
+  class DirectorPureVirtualException : public DirectorException {
+  public:
     static void raise(const char *msg) {
       // ... todo
       throw(DirectorPureVirtualException());

Lib/perl5/perltypemaps.swg

@@ -71,6 +71,10 @@
 /* raise exception */
 %define %raise(obj, type, desc) sv_setsv(get_sv("@", GV_ADD), obj); SWIG_fail %enddef
 
+/* For directors to raise/throw the original exception */
+%typemap(throws) Swig::DirectorException
+%{ sv_setsv(ERRSV, $1.getNative()); SWIG_fail; %}
+
 /* Include the unified typemap library */
 %include <typemaps/swigtypemaps.swg>