[Cuis] [Ann] Fix to Exceptions, New expression chain syntax and more!

[Juan Vuletich]

Hi Folks,

I've just commited to 
https://github.com/Cuis-Smalltalk/Cuis-Smalltalk-Dev a bunch of updates 
and a new image.

Biggest news is a fix to Exceptions. There was a serious bug: when there 
are nested handlers of the same exception, the wrong handler got run. 
See #testHandlerFromAction . This bug is common to Squeak and Pharo 
also. The fix was provided by Andrés Valloud.

Besides, Andrés did an extension to the Smalltalk syntax, using '::' for 
expression chaining. See #chainExamplesDoubleColon . I think it can help 
us avoid many opening parenthesis at the start of an expression, and 
many nested brackets in complex Boolean conditions. If you want to see 
how those expressions are written without the chain operator to compare, 
in #chainExamplesDoubleColon click on (show...) / decompile.

I also did tweaks to the compilation of #to:do: and #to:by:do: after a 
discussion in Pharo-dev, and to #vmParameterAt: after a discussion in 
Squeak-dev. And some minor tweaks here and there.

Thanks Andrés for your great contributions!

Cheers,
Juan Vuletich