Fully resolve potentially ambiguous symbols by removing using namespace statements from headers which have a cascading effect. This causes potential behavior changes when switching to c++11 since symbols can be exported from std and boost while both have been imported into the global namespace.

utils/rowgroup/rowgroup.h

@@ -59,7 +59,6 @@
 #include "../winport/winport.h"
 
 // Workaround for my_global.h #define of isnan(X) causing a std::std namespace
-using namespace std;
 
 namespace rowgroup
 {
@@ -1028,7 +1027,7 @@ inline void Row::setFloatField(float val, uint32_t colIndex)
     //N.B. There is a bug in boost::any or in gcc where, if you store a nan, you will get back a nan,
     //  but not necessarily the same bits that you put in. This only seems to be for float (double seems
     //  to work).
-    if (isnan(val))
+    if (std::isnan(val))
         setUintField<4>(joblist::FLOATNULL, colIndex);
     else
         *((float*) &data[offsets[colIndex]]) = val;