Octave: cleanup/restructure library files

- Restructure runtime code into declarations, function
  and class definitions, and initialisation code
- Rename internal functions/types to follow SWIG_Octave...
  or SwigOct... naming styles
- Style/comment/whitespace cleanups

Lib/octave/exception.i

@@ -1,6 +1,9 @@
+//
+// exception.i - C++ exception support
+//
+
 %include <typemaps/exception.swg>
 
-
 %insert("runtime") {
-  %define_as(SWIG_exception(code, msg), %block(%error(code, msg); SWIG_fail; ))
+%define_as(SWIG_exception(code, msg), %block(%error(code, msg); SWIG_fail; ))
 }