[Soot-list] Disable output for certain app classes

[Mario Mendez-Lojo]

Hi,

Because I don't know until runtime which classes of package 'x' I'm interested 
in transforming, I add the whole thing as a dynamic package

     Options.v().set_dynamic_package(Collections.singletonList("x"));

The transformation only affects a few of the classes in 'x': how can I specify 
that I only want to output those ones? I tried to set the rest as library 
classes, but then I get a concurrent modification exception because of modifying 
the chain of application classes while iterating over it.