Reduce possibility for collisions in moc generated files.

If two headers in different sub-folders both have the same filename and invoke the Q_OBJECT macro, reduce the possibility of conflicts in the generated files.

Consider the following files:

slider/view.hpp
button/view.hpp

If they both invoke Q_OBJECT macro, the resulting makefile will attempt to generate moc_view.cpp for each.

A possible solution is to detect such a conflict, and find the minimal difference in path and add a sentry for conflict mode. So the above would generate:

mocc_slider_view.cpp
mocc_button_view.cpp