qdoc: Adding a debug function

qdoc: Adding a debug function

qdoc segfaults for one user, when he runs
the release version of qdoc but not the debug
version. This change adds a -debug option to
the qdoc command line options. If set, qdoc
will print debug messages at useful milestones
so we can see where it is when it goes into
the weeds.

Change-Id: I0e826e74399eaf50091817c68c775d02c6b615d2
Reviewed-by: Jerome Pasion <jerome.pasion@digia.com>