refs #8824 Windose unhappy without MantidQT namespace

and though it can be compiled in some convoluted way, (and probably did on Jenkins) it is much better to have it declared.

Code/Mantid/MantidQt/CustomInterfaces/src/Indirect.cpp

@@ -39,6 +39,7 @@
 #include <QtCheckBoxFactory>
 
 using namespace MantidQt::CustomInterfaces;
+using namespace MantidQt;
 using Mantid::MantidVec;
 
 /**