There could be a case where the brute force removal is successful
in getting rid of a file, but the engine still tries to read this
file from disk later. Add defensive programming against this and
add a test.
Fixes#27
Add a method in ProjectResolver to query whether a source belongs
to the non-externally-built closure.
Use this to filter out files discovered when --follow-closure
is used to walk the closure.
Add a test.
For the benefit of the development environment, or any
users who only "git clone" this repository and work from it.
Fix the testsuite using this.
Rename the "adareducer" source dir to "ada_reducer"
