This could be useful in trying to track down when things break in special
ways.

Also fixes some other cosmetic changes needed for the project rename.

Ant build step had quite a mix: buildFile and antOpts expanded against
env, properties against buildVariables, and targets against both.
Now merging buildVariables into env and applying to all.

SlaveComputer.getChannelToMaster() can be null if Launcher is used to connect other VMs than the slaves.

So act gracefully