Move Math constants into class (to be consistent with other constants), tested against minGW / gcc 4.7.2 and fixed various issues (mainly initializer lists, unused variables). BlackMisc compiles now in MinGW, but still issues (especially with qDebug() friend methods)

src/blackmisc/display.cpp

@@ -112,9 +112,6 @@ namespace BlackMisc
         if (needSpace) { line += " : "; needSpace = false; }
 
         line += message;
-
-        static bool consoleMode = true;
-
         QTextStream out(stdout);
         out << line;
     }