#1 Improve "const correctness"

[Markus Elfring]

Would you like to apply the advices from the article
"http://en.wikipedia.org/wiki/Const_correctness" to
your sources?
I suggest to add the key word "const" to the type
specifiers for parameters like the following.
- controls (functions "mlSetControls", "mlSendControls")

http://cvs.sourceforge.net/viewcvs.py/oml-ri/ml/oss/lib/ml/common/include/ml.h?rev=1.1.1.1&view=markup

- q (functions "mlDIQueueGet.*Count")

http://cvs.sourceforge.net/viewcvs.py/oml-ri/ml/oss/lib/ml/common/include/mlqueue.h?rev=1.1.1.1&view=markup