Further exception cleanup

Use a new checked exception type (TJException) when passing through
errors from the underlying C library. This gives the application a
choice of catching all exceptions or just those from TurboJPEG.

Throw IllegalArgumentException at the JNI level when arguments to the
JNI function are incorrect, and when one of the TurboJPEG "utility"
functions returns an error (because, per the C API specification, those
functions will only return an error if one of their arguments is out of
range.)

Remove "throws Exception" from the signature of any methods that no
longer pass through an error from the TurboJPEG C library.

Credit Viktor for the new code

Code formatting tweaks

java/TJExample.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (C)2011-2012, 2014 D. R. Commander.  All Rights Reserved.
+ * Copyright (C)2011-2012, 2014-2015 D. R. Commander.  All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -351,7 +351,7 @@ public class TJExample implements TJCustomFilter {
   public void customFilter(ShortBuffer coeffBuffer, Rectangle bufferRegion,
                            Rectangle planeRegion, int componentIndex,
                            int transformIndex, TJTransform transform)
-                           throws Exception {
+                           throws TJException {
     for (int i = 0; i < bufferRegion.width * bufferRegion.height; i++) {
       coeffBuffer.put(i, (short)(-coeffBuffer.get(i)));
     }