[Kde-bindings] In qtruby, dispose causes irb to crash

[Stefano Crocco]

The following code makes irb crash:

require 'Qt4'

o = Qt::Object.new
o.dispose

The reason, of course, is that dispose returns the disposed object and that 
irb calls the inspect method of the value returned by each line. And since the 
object has just been disposed, calling inspect on it causes a crash.

In my opinion, this is a problem because it's very confusing for the user: he 
calls a method which should always succeed, and suddenly he gets a crash. The 
first time it happened to me, I took a while to understand the reason of the 
crash. 

There could be several ways to solve this problem. The easiest would be to 
make dispose return something other than the object, maybe nil. In my opinion, 
this would also make more sense than returning an object most of whose methods 
should not be called. Another option would be to change the inspect method to 
check whether the object is disposed and, in that case, to return something 
like "disposed".

Stefano