Correcting NSAffineTransform

[Fred Kiefer]

Ken Ferry just send me testing results from Cocoa that seem to prove, 
that the GNUstep implementation of prependTransform: and 
appendTransform: are the wrong way around. This is due to the fact, that 
the documentation from Apple is rather confusing, but, as I convinced 
myself after hard thinking, is mathematically correct.

We will need to exchange the code of this two methods and also inspect 
all their usages. There are, for example, the GNUstep extension methods 
concatenateWith: and concatenateWithMatrix:. I am not sure, if these 
also need correcting or if the former could just be changed to use 
prependTransform, wheras the later could be left unchanged?

In GUI appenTransform: also gets used in NSView and NSPrintOperation. 
And both methods get used in the backends. Here a simple exchange of the 
calls should do.

As this is a dangerous process I would like to hear a few comments 
before I start it.

Fred