Remove obsolete logging framework

This changes removes classes of the obsolete logging frame work and
all its references. It was not used anywhere, but included in several
headers.
Had to add header QDateTime in some places, which was not correctly
included and now missing.

refs #90

samples/blackmiscquantities/samplesphysicalquantities.h

@@ -7,7 +7,6 @@
 #define BLACKMISCTEST_SAMPLESPHYSICALQUANTITIES_H
 
 #include "blackmisc/pqconstants.h"
-#include "blackmisc/debug.h"
 #include <QDebug>
 
 namespace BlackMiscTest {