Option to exclude modules from instrumentation

[aronisstav]

Concuerror needs to instrument all code to be able to reset the state of a program after each scheduling it attempts. You could use an option to exclude a module from instrumentation, but then you need to ensure that any state is reset correctly (e.g. by calling a function in the excluded module that initialises/resets the relevant parts of the state before the test starts; cleanup in the end is not sufficient as an interleaving may not reach it); Concuerror may complain if the program behaves differently, if no 'known race' has been reversed when exploring new schedulings.