[LLVMdev] Exception Implementation Example added to Wiki

[Garrison Venn]

I just added an exception example to the wiki intended to be run in a JIT environment. Although this information is heavily date dependent, 
as the LLVM exception subsystem will be modified as time goes on, I could have used such an example when I was looking into this; hence the submission.
Having said this, I'm not an LLVM expert, and even though the code works, I'm sure there are omissions and inaccuracies, so if the experts have
the time ...

Hopefully some members of the community will find this beneficial

Garrison 

PS: Is there a better to upload source to the wiki than merely pasting it in? Only image file types seemed to be allowed for upload.