unit tests for dbug


dbug/Makefile.am:
  unit tests for dbug
dbug/dbug.c:
  negative lists (-#-d,info => everything but "info")
include/my_dbug.h:
  negative lists (-#-d,info => everything but "info")
unittest/Makefile.am:
  unit tests for dbug
dbug/tests-t.pl:
  unit tests for dbug
dbug/tests.c:
  unit tests for dbug