nsDebug Support

[Doug Turner]

I have landed a new implementation of nsDebug that can be used when 
linking directly to XPCOM and when using the XPCOM glue library. 
nsDebug now depends on an interface known as nsIDebug.  This allows 
xpcom glue to use the same version of the code as the xpcom library uses 
thus both reducing footprint as well as ensuring that you get all of the 
functionaltiy in nsDebug in both glue and non-glue modes.

In C++ code, you should not directly use nsIDebug, but rather use the 
wrapper class nsDebug for your needs.

nsIDebug is marked as UNDER_REVIEW.  I plan to freeze it for the 1.5 
milestone.  If we make any changes between now and 1.5, we will change 
the IID of the interface.

Regards,

Doug Turner